Tuesday, May 13, 2025

Dusty Days

The past to days were quite dusty thanks to strong south winds in advance of a slow moving cold front that finally moved into the Salt Lake Valley last night.  Yesterday was the worst of it with dust filling the Salt Lake Valley in the afternoon, creating and apocalyptic scene.  

Scene looking south over the Salt Lake Valley from the upper Avenues at 6 PM

Observations from the University of Utah over the past two days show persistent southerly flow on Sunday with peak gusts reaching 40-45 miles per hour.  Those winds died down Sunday night before strengthening Monday morning.  The strongest winds of the period occurred Monday with gusts > 35 mph common from about 1100 to 2100 MDT and a peak gust of 48 mph.  

Source: MesoWest

A look at MesoWest data shows many valley locations in central and western Utah had peak gusts more than 50 mph.  A few examples include Parowan (61), Curlew Junction (60), Stockton (60), Simpson Springs (58), Baccus/SR111 (58), and I-215 at I-80 (58). 

The exposed lake bed of the Great Salt Lake gets a lot of attention for dust, but widespread, prolonged events like this tend to be pre-frontal with dust sources to the south, southwest, and west.  GOES satellite imagery from yesterday afternoon shows many dust sources over western Utah.  With yellow arrows I've highlighted four.  The first two are the playa area near Fish Springs in western Utah.  Another is in the Skull Valley.  A lot of dust was produced in these areas, but did not affect the Salt Lake Valley yesterday (although dust from these areas could have come in with the cold front last night).

Source: CIRA

The fourth in the southern part of the image and appears to be the Wah Wah Valley Hardpan south of the Sevier Dry Lake Bed.  It's unclear if dust from this area reached the Salt Lake Valley yesterday or extended into environs to the east.

The sources for the Salt Lake Valley, however, appeared to be many in the areas that I've circled in blue.  There appear to be many emission hotspots in this area, without any one obvious in this visible satellite loop.  Just to the west of it though I've identified one clear hot spot that produced a plume that one can clearly trace into the western Salt Lake Valley.

That plume emerges from an area that is near SR-36 between Vernon and Eureka and just to the west of Boulter Peak.  This is an area that was burned during the Boulter 2024 fire.  My best guess is that the burn scar is the source of this plume (h/t to University of Utah Research Assistant Professor Derek Malia for pointing this out).  

Source: https://app.watchduty.org/

Burn scars have been important sources of dust for the valley in the past.  The Milford Flat Fire (2007) was the largest wildfire in Utah history and its scar was a prolific dust producer for many years.  Fortunately, the land surface there appears to have recovered and is more resistant to dust emissions today.  

Monday, May 12, 2025

Could Snow Storage Work in Utah?

It's that time of year when I wish we could save some of the snow from this season for next season.  There's a dense snowpack at upper elevations and wouldn't it be great if we could save just some of it for next year.

Some resorts in Europe have been doing that, piling up snow and covering it with white, insulated blankets or sawdust to save it until next season.  Levi in Finland is perhaps best known for doing this (see https://www.wired.com/story/ski-resorts-are-stockpiling-snow-to-get-through-warm-winters/).  Now Sun Peaks Resort has become the first resort in Canada to do it.

Per the video above, they invested $170,000 (presumably CDN) for geotextile blankets to preserve snow for next season to use it in late fall and early winter.  

I don't know enough about resort economics, snowmaking costs, or snow energy balance to evaluate whether or not this would work here, but I'm intrigued.  Beyond costs, one advantage of this approach is that the preserved snow would be available even if snowmaking conditions were unreliable, such as might occur during a warm fall.  

At issue is how well this would work at a lower latitude.  I am aware of the use of geotextiles in the Alps to preserve glaciers, but am unaware of tests at at our latitude.  One could imagine using terrain maps to evaluate the total incoming solar radiation during the warm season, storing the snow in areas that minimize the total incoming solar radiation due to favorable aspects and shading by the surrounding topography.  

At Alta, could you stockpile snow at the base of Ballroom or below the shoulder traverse to cover Main Street next season?  

Saturday, May 10, 2025

Last Day of 100 at Alta?

At 1 PM MDT this afternoon, the total snow depth at Alta Collins dropped to 99", falling below 100" for the first time this melt season.  There are a couple of cold troughs coming next week so a recovery is not impossible, but given that we're losing about 3" a day right now and have a couple warm days ahead, the odds are such that today was probably the last with a 100" snow depth this season.  

Cover in Collins Gulch remains excellent.  The snow earlier this week buried the snirty snow surface in some areas, especially on high north, making for a bit of a white corn harvest at upper elevations.  

Photo: Erik Steenburgh

Photo: Erik Steenburgh

Although there was a shallow freeze overnight thanks to the radiative cooling of the snow surface, given the warmth (the overnight low at Collins was 43) and the high elevation sun, it didn't take long for things to soften up anywhere that was in the sun.  We were off the mountain at 11 and eating tacos in the shade at Lone Star shortly thereafter.  In other words, a great May ski day. 

Friday, May 9, 2025

NSF Cuts Shutter NSF Unidata

There's an organization you may have never heard of, but if you are a user of weather data and graphics on the web, they have almost certainly contributed to the cyberinfrastructure that made it possible.

Their name is NSF Unidata, or just "Unidata" for short.  

Unidata developed organically in the 1980s when Universities has a pressing need to access weather data in real time, but couldn't.  The Internet at the time was nascent and there was essentially no hardware and software systems capable of delivering, processing, and analyzing weather data.  In 1983, a workshop at the University of Wisconsin involving about 80 US atmospheric sciences programs coined the name "unidata" and recommended that it be developed to provide:

  1. Access to current and archived weather data, including satellite imagery and forecasts.
  2. Support interactive computer capabilities at universities.
  3. Communications capabilities between universities, the National Center for Atmospheric Research, and NASA.
These are things that we take for granted today, but would not have happened without Unidata.  Amongst the products they developed are the Local Data Manager (LDM) which acquires and shares data between providers and users like the National Weather Service, NASA, and universities; netCDF (Network Common Data Form) which is a file format for storing self-described, multidimensional scientific data; and metpy which is a collection of python tools for reading and processing weather data.  They have been transformative for the atmospheric and related sciences, with benefits not only for universities, but also the private and academic sectors and across the world.  

I have benefited and been actively involved with Unidata throughout my career, including volunteer service on their Users and Strategic Advisory (formerly Policy) Committees.  Last year I gave a short virtual talk on Unidata's history that provides some examples of the various ways that Unidata has benefited my career and the atmospheric and related sciences as a whole (apologies that the initial part of the talk is cutoff in the video below).


On 30 April, the National Science Foundation (NSF) froze funding for Unidata, with instructions to stop all funded actions until further notice.  Due to this freeze, most staff in the Unidata program center are being furloughed effective today.  The impacts on are fully summarized below.  


This is yet another example of the damage being done to the US scientific enterprise by the Trump Administration.  Unidata is an example of an organization that has widespread support from the University community because it develops and provides essential scientific services for research and education in the atmospheric and related sciences.  The radar feeds that you take for granted today on your smart phone were first developed by the Unidata CRAFT product.  The distribution of model forecasts that you can access today was first developed by the Unidata CONDUIT project.  And a lot of the graphics that you see on the web rely on Unidata MetPy and visualization software.

These disruptions of the scientific enterprise are pure insanity.  The halting of funding to Unidata will stymie scientific advancement, slow educational innovation, and limit classroom experiences.  

Monday, April 28, 2025

Blog Break

I'm going on a temporary hiatus for a couple of weeks.  Blogging may be light to non existent.  Congratulations to all of the University of Utah graduates, especially those from atmospheric sciences.  

Wednesday, April 23, 2025

A Quiet April So Far

In a post last week I commented that it had been a dry April so far.  We got a bit of rain with the trough I discussed in that post but for the most part this April has not only been dry but quiet.  April is sometimes a month with strong cold fronts and big temperature swings.  My view is that this one has been rather ho-hum without a lot of fireworks. Temperature swings have been modest and rainfall somewhat scant.

Rainfall through yesterday for the month at the Salt Lake City International Airport was only 0.44 inches.  Data from the National Weather Service shows that much of Utah is below average for precipitation over the past 30 days.

A weak system moving through will bring some clouds and a chance of showers to northern Utah over the through Thursday, but accumulations look to be unimpressive.  There is a deeper trough approaching for Sunday and Monday.  Keep your fingers crossed it delivers some rain as we could use it.  

Saturday, April 19, 2025

More Proposed NOAA Budget Cuts

The Trump Administration 2026 budget passback plan would be catastrophically bad for weather prediction in the United States.  

Below is a transcript of the letter that I sent to Utah Senator John Curtis and Representative Blake Moore concerning these potential cuts.  If you agree (or even if you disagree and want to share an alternative opinion), please consider writing your legislative leaders.   

--------------------------------------------------------------------------------------------

I am a Professor of Atmospheric Sciences at the University of Utah who has worked for 30 years to improve weather prediction in Utah.  I lead research to improve the understanding and prediction of winter storms in Utah’s mountains and develop methods to improve snowfall forecasting across the continental United States using artificial intelligence. The forecast techniques my group has developed are used by the National Weather Service and private companies.  I am also proud to have served as the graduate advisor for several Air Force officers who are contributing to weather support for our Nation’s defense.  I write today as a private citizen.  The views expressed in this letter are mine and independent from the University of Utah.  

The Trump Administration’s 2026 budget passback plan would be catastrophic for the future of weather prediction in the United States, reducing our ability to anticipate, prepare, and respond to high-impact weather including winter storm, severe thunderstorm, and wildfire hazards that affect Utah.  It would gut the NOAA Oceanic and Atmospheric Research Office, 10 NOAA Research Laboratories, and 16 Cooperative Institutes, essentially eliminating nearly all of the critical research done by NOAA.  

We are already seeing the impacts of the Trump Administration on the National Weather Service and the broader US Weather Enterprise.  National Weather Service offices, due to staffing cutbacks, are reducing overnight staffing at forecast offices, decreasing the frequency of weather discussions for fire weather and spot forecasts, lowering the frequency of weather discussions for aviation forecasts, and making decisions for critical some watch/warning/advisory products only on day shifts (see, for example, https://www.documentcloud.org/documents/25899644-changes-coming-to-nws-sacramento-products-services/). 

The 2026 budget passback plan, however, would not only further degrade National Weather Service forecasts and decision support services during critical high-impact weather events, but halt ongoing research to advance satellite, radar, and other observing systems; create next generation computer forecast systems; and expand the use of artificial intelligence for weather watches and warnings.  These cuts will have significant impacts on future weather prediction in Utah, which given our climate and complex terrain is highly variable and stands to benefit greatly from advances in the areas above.  Let me give three examples: 

Winter storm forecasting.  Utah’s complicated geography, topography, and water features such as the Great Salt Lake produce extremely localized snowstorms that are not well forecast by current National Weather Service forecast modeling systems.  In other countries with complex terrain, such as the Alpine nations of Switzerland, France, and Austria, computer models are being run at much higher resolution to account for terrain effects. There is tremendous potential for improved forecasts for Utah if NOAA can continue its computer model development efforts.

Coupled atmosphere-fire modeling.  Currently, there is no operational capability to simulate and forecast the interactions between wildfires, vegetation, and the atmosphere that cause wildfire blowups and severe wildfire behavior.  Ongoing research is building modeling systems capable of doing this and advancing our ability to better anticipate wildfire spread in the future.

Seasonal water-resource prediction.  Long-lead-time forecasts of temperature, precipitation, and mountain snowpack are vital for anticipating the spring runoff.  Future advances in our understanding and prediction of year-to-year variations in snowfall and spring snowmelt dynamics will enable our water managers and agricultural communities to make better decisions.

Recently, the American Meteorological Society and National Weather Association, which represent all of these sectors, released a statement summarizing the implications of these cuts (https://blog.ametsoc.org/tag/ams-statement/).  It summarizes well the importance of NOAA for the Nation: 

Without NOAA research, National Weather Service (NWS) weather models and products will stagnate, observational data collection will be reduced, public outreach will decrease, undergraduate and graduate student support will drop, and NOAA funding for universities will plummet. In effect, the scientific backbone and workforce needed to keep weather forecasts, alerts, and warnings accurate and effective will be drastically undercut, with unknown — yet almost certainly disastrous — consequences for public safety and economic health.”

I ask that you evaluate the proposed cuts, their impacts on the protection of lives and property in the State of Utah, and the potential benefits that will be lost if these cuts are enacted.  NOAA research is an investment that greatly benefits Utah and the Nation.

Thank you for your consideration.

Sincerely,


Dr. Jim Steenburgh


Friday, April 18, 2025

Why Small Majors Are Important at a University

Whether it be the federal government, the state government, or the University of Utah, there is a lot of talk these days about "efficiency."  Google AI defines efficiency as "how well resources are used to produce desired outputs, often measured by the ratio of outputs to inputs."  

One of the bills passed this last state legislative session, HB 265: Higher Education Strategic Reinvestment, requires a reallocation of $20 million to the University of Utah's base budget to move support from inefficient operations and programs to efficient ones.  Specifically, the U is to "develop a strategic reinvestment plan that:

(i) identifies programs, courses, degrees, departments, colleges, or other divisions of the institution, operational efficiencies, and other components of the institution's instruction and administrative functions, including dean positions and other administration positions, that merit further investment;

(ii) identifies programs, courses, degrees, departments, colleges or other divisions of the institution, operational inefficiencies, and other components of the institution's instruction and administrative functions, including dean positions and other administration positions, that the institution will reduce or eliminate to shift resources, in an amount at least equal to the amount of reinvestment funds dedicated to the institution."

The U must submit of a draft of their plan to the Utah System of Higher Education (USHE) in May.  

Recently, the University of Utah was told by leaders of USHE to look at cutting majors with fewer than 40 graduates per year.  The Salt Lake Tribune article in that link stated that U Provost Mitzy Montoya "bristled at the number, which she said feels arbitrary."  I'd like to take a deeper diver here into some of the reasons why the number of graduates in a major can be a poor metric to use in isolation and why small majors are important to a University. 

Some of these are noted in the article, including the fact that a program may be smaller but growing, but there are others.

In some cases, a department or departments may offer multiple majors.  There may be small enrollment in one of those majors, but the costs of offering may be relatively low since most of the classes needed for it are offered anyway.  This is the case for the recently developed Earth and Environmental Science major, which is not housed in a department but instead spans multiple departments and largely builds on the existing curriculum in Atmospheric Sciences, Geology and Geophysics, and Biology.  This is also a new major and growing fast (I suspect it is now well over 40 majors). 

In other cases, the major may be small, but vital to society.  Mining Engineering is such an example. This is a specialized engineering discipline that is important to the State of Utah.  The department is small, but graduates have high salaries and a high employment rate.  And they are needed.  

A department might also have a small number of majors, but teach high-demand classes.  In my area, Atmospheric Sciences, we graduate a relatively small number of students each year, but also offer some of the largest enrolled physical sciences classes on campus.  I have more than 500 students in my class this semester.  It's online and "very efficient," although students also tell me they love it and learn a lot!  We also offer higher-level classes in climate, environmental programing, environmental statistics, and other areas that are required or needed by students in other majors.  It takes a village and specialty disciplines are often essential for student education.  

Then there are small departments on campus that are very innovative and successful in research and innovation.  This includes my department, but also departments like Metallurgical Engineering and Pharmacology/Toxicology.  These departments have the highest ratios of research funding per faculty member on campus, with external funding that greatly exceeds their state budgets.  

I've focused above on science and engineering, which reflects my experience on campus, but there are also strong arguments for keeping smaller departments in the humanities and other areas.  

Increasing efficiency by reducing waste is important.  However, it should not be evaluated based solely on the number of graduates.  The real goal for a University and its various units isn't efficiency but value, for its students and society, with value here being broadly defined to include non-monetary benefits and impacts.  Just read the University of Utah's mission statement:

"The University of Utah drives unsurpassed societal impact by preparing students from diverse backgrounds to be leaders and global citizens who strengthen our society and democracy; generating and sharing new knowledge, discoveries and innovations that supercharge our economy and improve lives locally, nationally and globally; and engaging local, national and global communities to promote education, health and quality of life."

Those intangibles matter and we need to be cautious about using metrics that don't adequately measure them.  

Thursday, April 17, 2025

Joint AMS/NWS Statement on NOAA Research Cuts


"The scientific backbone and workforce needed to keep weather forecasts, alerts, and warnings accurate and effective will be drastically undercut, with unknown — yet almost certainly disastrous — consequences for public safety and economic health."

See the full statement: https://www.ametsoc.org/ams/about-ams/ams-statements/statements-of-the-ams-in-force/stand-up-for-noaa-research-the-time-to-act-is-now/ 

Tuesday, April 15, 2025

Where Are the April Showers?

It's been a dry start to April with only 0.16" of precipitation at the Salt Lake City International Airport, 0.15" of which fell on April 1st.  We won't see precipitation today, so that will be the tally through the half-way point of April, which will tie it for the 9th driest first half of April on record.  If you are wondering, there are five Aprils in which we had no measurable precipitation in the first half of the month, most recently in 1992.  

The April Fools storm was a bigger producer in the Avenues Foothills than the airport, but my full-sun gardens are now starting to dry out.  We could use some April showers soon.  

The likelihood of valley precipitation will finally be on the increase late Wednesday into Thursday as an upper-level trough digs into Utah from the Pacific Northwest.  The GFS shows the trough over central Idaho at 1200 UTC 17 April (6 AM Thursday) with some showers across northern Utah with the accompanying cold front. 


Right now this doesn't look like a supersoaker, except if maybe you are lucky enough to be one blessed with a more intense shower or thunderstorm, but it will cool things down and give us some showers.  We'll call it beneficial rains for the valley (maybe even mixed with some flakes for the benches on Thursday and Friday) and a return of mountain snow.  

Given the unsettled nature of this spring pattern, the spread for water equivalent and snowfall in the Utah Snow Ensemble for Alta is enormous and about as big as I've seen all winter.  


Odds are probably best on Thursday.  After that, it will probably come in fits and starts if it keeps coming.  The dendrites will have a real battle with daytime heating.  Good skiing will probably require high end accumulations and getting on it right away.

Friday, April 11, 2025

Mainly Dry Cold Front

Pickin's are slim this week for weather entertainment, although I'm hoping you are getting out for some time in the sun.

On tap for tomorrow is the passage of what looks to be a mainly dry cold front, which is due to arrive tomorrow morning.  The overnight GFS forecast shows the front at 700-mb (10,000 ft or crest level) pretty much right over northern Utah at 1500 UTC 12 April (0900 MDT Saturday).   

By 0000 UTC 13 April (1800 MDT Saturday), the flow has finally come around to west-northwesterly and 700-mb temperatures have dropped to about +4C over the Salt Lake Valley from +9C today.  So tomorrow will be cooler, but still mild, with valley highs in the low 70s and 9500 foot highs in the mid to high 40s. 

Sunday the 700-mb temps will be down even lower and our machine-learned forecast for Little Cottonwood is calling for temps at Alta-Collins  and on Mt. Baldy to be near or just above 20°F.  


Thus, although there may be some clouds around, it looks like we may get a pretty good hard freeze Saturday night. Given the lack of snow, I'm expecting coral reef conditions on Sunday morning.  Patience and playing solar aspects right will be the key to finding corn. 


For now, there's nothing major on the horizon.  We may go deeper into April without a big storm since the April Fools Powder Surprise.  On upper-elevation north aspects in the central Wasatch, peak snowpack water equivalent is often in late April.  I'm starting to wonder if that will be the case this year.  

Tuesday, April 8, 2025

Dry Post April Fools

April got off to a good start with the April Fool's storm, but since then, it's been dry.  That dry streak looks to continue through the work week with all members of the Utah Snow Ensemble flatlined for Alta-Collins until 1200 UTC 12 April (6 AM MDT Saturday).  

A few members are excited about snow on Saturday night and Sunday, but most are producing snowfall amounts in the low single digits.  The reason for this is a compact upper-level trough expected to move across the northern Rockies over the weekend.  At 1800 UTC 13 April (Noon MDT Sunday), it's centered over Montana in the latest GFS forecast. 


The trough is fairly dry on its south side, so most of the model runs are giving us a good hard freeze but not a lot of snow.  Basically a good recipe for bone-rattling coral reef conditions, perhaps with a skiff of snow on top on Sunday.  Sounds bad.

If the trough can dig more than currently advertised by most of the members, perhaps we can do better.  About 10% of the ensemble members produce 10" or more by 6 PM Sunday.  Those odds are long, so yardwork is looking like a good option unless things change.

Friday, April 4, 2025

It's Better to be Lucky than Good

Yesterday was one of those days when if you were skiing at Alta in the afternoon, consider yourself blessed or, alternatively, it's better to be lucky than good. 

From 1100 to 1600 MDT, Alta-Collins picked up 9" of fresh, including 3" in an hour from 1200 to 1300 and then again from 1400 to 1500.  Water equivalent was .46", so this was 5% water content.  Winds on Mt. Baldy during that period never guested over 10 mph.  

I took a look at forecasts from the 12Z models on the prior day (2 April) and the GFS was going for nothing.  The HRRR .15" water and 2.7" of low-density snow.  Even yesterday morning, expectations were low.  The Utah Avalanche Center Forecast that morning called for 0.5 to 1" of snow.

This isn't to throw them under the bus as they do a great job, but just to illustrate that yesterday's snowfall was pretty unexpected.  It wasn't handled well by the models or the forecasters.  So what happened?

Well, morning broke with not much happening other than a few scattered snow showers.  At 1459 UTC (0859 MDT), there were some light returns on radar, but nothing to get excited about.  


However, the flow was light and the airmass unstable, and with a little surface heating, convection began to get going.  By 1857 UTC (1257 MDT), during an hour in which Alta picked up 3" of snow, localized convective snow showers had developed over portions of the central Wasatch, especially around Little Cottonwood, and the high terrain down to Mt. Timpanogos.  


Even then, the radar wasn't all that impressive, but the relationship between radar reflectivity and snowfall rate is not a good one.  Low-density snow of the type that fell yesterday often doesn't light up radar screens.  This is why it's so valuable to have weather cams and automated snow depth sensors to monitor actual conditions at the ground.  

The development of the first snow showers over high terrain was probably favored by the light flow and unstable conditions, with daytime heating yielding upslope flow and convergence over the mountains.  

The convection became more widespread with continued surface heating as evident in the 2033 UTC (1433 MDT) radar image from another period when Alta got 3" in an hour.  Nevertheless, snow showers persisted over upper Little Cottonwood.  


It's very difficult to reliably predict the location and intensity of these snow showers.  We can anticipate their development, but questions of where, when, and how intense are hard to answer reliably.  Neither our current models nor human cognition are very good at distinguishing a situation like the one yesterday from one where the snow showers are less productive and maybe provide light accumulations. The processes are simply too small in scale and too sensitive to small changes in the atmospheric stability and moisture content.  Basically, yesterday really was a tough forecast, at least with lead times of more than a couple of hours. 

I suspect if you were skiing yesterday afternoon, you probably didn't care.

Thursday, April 3, 2025

About That New Ski Resort in the Oquirhhs...

Hopefully most of you have figured out that the previous post, New Ski Resort to Open in the Oquirrhs, was April 1st foolery.  

A good April fools joke needs to be somewhat believable, so let's break down that post a bit more.

First, the idea of development and possibly a ski resort in the Oquirrhs is quite believable.  Surely as the Wasatch Front metro area expands and the Salt Lake, Tooelle, and Utah Valleys are paved over, there must be developers with an eye on the undeveloped island that is the Oquirrhs.  In fact, Kennecott Land once spoke quite seriously about building a ski resort on their property in the Oquirrhs.  If a ski resort can be built in the snow desert and scrub oak of the Mayflower area, eventually one will probably come to the Oquirrhs.  

Is snow as plentiful in the Oquirrhs as the Little Cottonwood?  No.  The Rocky Basin Settlement Snotel in the southern Oquirrhs at 8700 feet has a median peak SWE of 24 inches compared to 43 inches at 9100 feet at Snowbird.  The Rocky Basin Settlement number though is pretty close to the 25 inches at Thaynes Canyon (9250 ft) in the upper reaches of Park City Mountain Resort.  However, the Oquirrhs also get about as much lake-effect as the Cottonwoods.  Below is the water equivalent snowfall (left panel) produced in lake-effect storms showing that the SNOTELs in the Oquirrhs are on par with Mill D North and Snowbird.  


Is there a powder Shangri-La as I suggest in the post?  Probably not.  I haven't been touring in the Oquirrhs this winter as suggested by the post, but I have in the past.  My guess is that there is no magic microclimate like Little Cottonwood in the Oquirrhs, although there are more mountain lions and fewer people.

Is snow farming from season to season a real thing?  Yes it is.  That article from Levi was real.  They are piling up snow, preserving it beneath geotextile blankets, and using it to open the following season.  Could such a thing happen in Utah?  I don't know, but there is the expertise at the U to figure it out and it strikes me as potentially being worth looking into as it preserves water, energy, and money.  Perhaps it would be most feasible at a place like Alta which typically closes when the snowpack close to its deepest so there's no impact on their skiing business to pile up the snow at the time of peak snowpack.  Maybe they could preserve enough to have cover for Mambo->Corkscrew come the next November.  Or Main Street where there's no snowmaking but maybe they could preserve snow near the base of Mt. Baldy which has less total incoming solar due to topographic shading.  

And finally, we have the extension of the red-line Trax into the Oquirrhs.  That was pure fiction designed to give away the April 1st foolery.  There are no such plans.  We can't even get rail to our current ski areas.  

Tuesday, April 1, 2025

New Ski Resort to Open in Oquirrhs

Over the past several months I have been working with a group of investors developing a new ski resort for the Oquirrh Mountains west of Salt Lake City.  My non-disclosure agreement expired today, so I thought I would take the opportunity to talk about their plans.  

The Oquirrh Mountains have extensive amounts of private land, mainly owned by Rio Tinto/Kennecott.  This investment group, however, owns approximately 8000 acres of land near the ghost-town of Ophir at elevations between 7000 and 10000 feet elevation.  You haven't seen me much in the Wasatch this winter because I've been doing a lot of ski touring on the property, avoiding crowds and getting to know the dry powder of the Oquirrhs on an intimate basis.  


I thought snowfall wouldn't be as plentiful as in Little Cottonwood, but after skiing a season there, I'm pretty certain the resort gets more.  It's simply an incredible microclimate, fueled by lake effect funneled into a terrain concavity.  If you think Alta gets a lot of snow in northwest flow, wait until you see this place in northerly flow.  I've toured in five storms with snowfall rates of more than 4" an hour.  There's little doubt that this is the future of lift-served skiing in northern Utah.  

In addition, to provide insurance against climate change, the investors have secured substantial water rights for snowmaking and are planning on developing Utah's first extensive use of snow farming in order to recycle snow from season to season.  They have hired an expert from Levi, Finland, where this is now being done to preserve snow from one season to the next.  

In fact, they are planning a trial run as they build out the resort over the next 18 months.  Next season, while they will still be under development, they will start making snow on what will be their signature run, Showcase. Comparable in length and pitch to famed upper, mid- and lower warm springs run at Sun Valley, the plan is to blow snow into deep piles next winter and then preserve those piles through the summer by covering them with white, geotexttile blankets to reflect sunlight and insulate the snow piles, allowing as much as 70% of the snow to survive through the warm season.  

They then plan to open the 2026/27 season in mid September with 3000 vertical feet of skiing on Showcase.  They expect to do this each season moving forward, pipping Snowbird for Utah's longest season.  

The main challenge at this stage is figuring out how to get people to the base of the resort.  The investors are currently working with UTA on plans for an extension of the Trax Red Line through an old mining tunnel in the eastern Oquirrhs.  Incredibly, this tunnel is built at grade, allowing light rail to deposit skiers at the base of the resort without having to use an expensive cog-railway design.  

I anticipate that this development will completely transform skiing in northern Utah.  Once skiers get an appetite for the dry powder of the Oquirrhs, Little Cottonwood will be an afterthought and the red snake will be dead.  

Sunday, March 30, 2025

What Causes "Flat" Light

The quality of light strongly affects one's confidence as a skier.  On a sunny day, most of the solar energy (about 85% of it when the sun is high in the sky) is direct, meaning that it is traveling along a straight line from the sun to the Earth's surface.  This results in large brightness contrasts between directly illuminated surfaces and those in shadows.  Even subtle textures in the surface of the snow are easily seen.  

Descending a groomed run at Ischgl, Austria on a sunny day dominated by "direct" solar energy.

All else being equal, it is much easier to ski on such days.  It is easier to see the steepness of the terrain, variations in the snow surface, and subtle changes in the snow conditions.  

However, on day with thick overcast, even high overcast, the light can be "flat." Flat light is a colloquialism for situation in which there are no shadows, as was was the case at times at Alta today (Sunday).  

Flat light at Alta on Sunday, March 30th

Flat light is produced when most of the light from the sun isn't direct but is instead diffuse.  When skies are covered by thick clouds, the sunlight is not direct because it has been scattered by the liquid water and ice particles in the clouds.  As a result, the Earth's surface receives sunlight from all parts of the sky, resulting in a lack of shadows.  This is particularly problematic for seeing contrasts in a white surface like snow.  

High clouds sometimes vary in depth, so on a day like today, there can be variations in the flatness of the light.  Below is a photo I took looking up upper Sleepy Hollow off the Supreme Chair at 11:07 AM.  At that time, the sun was only partially obscured and there was enough direct radiation for the trees to cast shadows and for one to see some texture in the snow, as evident in the foreground of the picture.  


On our next run, at 11:33 AM, the sun was nearly obscured and there was considerably less direct radiation.  Shadows were less apparent and the texture and variability of the snow were harder to see.  


Such conditions though are not anywhere near as bad as they can get.  Add fog and one can have a hard time telling up from down.  Balance becomes difficult and one can even suffer from vertigo.  

Goggles can help some.  Color tints with higher light transmission that enhance contrast are usually best on flat light days.  Skiing closer to trees and other darker objects can also help.  

One of Bruce Tremper's ten commandments of avalanche safety is "thou shalt never go first."  This commandment is especially important on powder days with flat light, as a set of tracks helps to provide some contrast in an otherwise featureless landscape.  Be generous to your friends on these days and let them have first tracks.

Friday, March 28, 2025

Dusty Spring Morning

With yesterday's strong south winds, dust moved into Salt Lake Valley and environs yesterday and lingers this morning with visibility somewhat reduced as one looks to the central Wasatch from the University of Utah.

Source: https://home.chpc.utah.edu/~u0790486/wxinfo/cgi-bin/uunet_camera_explorer.cgi

Observations from the University of Utah show strong south winds yesterday afternoon and evening with PM2.5 levels increasing after about 1600 MDT from 3 to 8 ug/m3.  After settling some through 0200 MDT, they then climbed again to 13 before settling some this morning.  


These numbers are not high and are at good to low-moderate air quality levels, but nevertheless, there's plenty of dust in the air.  

Give the overall flow yesterday, the dust in the Salt Lake Valley was likely from sources to the south and the southwest given the flow direction and not from the exposed Great Salt Lake bed.  The flow direction was such that if there was dust emitted from the Great Salt Lake bed, especially Farmington Bay, it would have been transported to the northern Wasatch Front.  I'm not sure if there could be a some dust from the lake bed mixed in now given the shift to northwest flow last night but I suspect most of this is still from origins to the south and southwest. 

Thursday, March 27, 2025

Dry Spring -> More Typical Spring

The work week has proven spectacular with mostly sunny skies and mild temperatures.  "Anything season" is here, meaning that you can do pretty much any type of recreation you desire, sometimes on the same day.  The lower-elevation trails have dried out now in many areas and are quite passable for hikers and bikers. Meanwhile, we still have a deep snowpack at upper elevations.  

Today's sunrise from the Avenues foothills.

We will, however, be transitioning from the dry spring pattern we've experienced the last few days to a pattern that will bring the occasional mild spring storm system to northern Utah.  This transition won't necessarily be abrupt as a couple of weak systems move through Friday and Saturday.  After that, there's a series of troughs that move through.  It's not easy for me to summarize my expectations for the timing and strength of these storms as there's a good deal of variability in the Utah snow ensemble.  Just look at the spread at the end of the 10-day period.  

The best way to summarize this is perhaps simply to say changeable, with the occasional mountain snowstorm interspersed with breaks.  It's a time for adaptation to what Mother Nature brings rather than having strong expectations for what's to come.  Fortunately, spring in northern Utah means a plethora of options.  

Tuesday, March 25, 2025

Downtime for weather.utah.edu

Due to utility work at the University of Utah data center, weather.utah.edu is expected to be down for approximately two days.  Don't shoot the messenger. 

In the meantime, enjoy the sunny, warm March weather and stop worrying about the next storm.  The forecasts looked like spaghetti anyway, so who the hell knows what's going to happen.  

In the meantime, for your entertainment purposes, there were some beautiful lenticular clouds over the central Wasatch yesterday.  


Such clouds are produced by mountain waves, up and down motions produced by the interaction of the atmospheric flow with the topography.  The clouds form where the flow is forced up and dissipate where the flow is forced down.  The layering is produced by vertical variations in relative humidity, which causes saturation in areas of ascent to be reached at different levels of vertical displacement.  

Lenticular clouds have been confused with flying saucers.  Let's not let this start a social media conspiracy theory.  

Thursday, March 20, 2025

Avenues Avalanche!

Let's have some fun with a post based on what I'll call "sidewalk science."  

The Hall of Fame Baseball catcher Yogi Berra once said "you can observe a lot just by watching."  This applies for sure to both meteorology and snow science.

This afternoon, right near my house, I encountered an avalanche in the front yard of a house on 16th Avenue in the upper Avenues.

Oh, I didn't actually see the avalanche happen, but I did see the aftermath, which I've summarized in the below.  It contains many of the hallmark characteristics of an avalanche.  The first is the starting zone, which in this case I measured to be 35°.  Most avalanches start on slopes between 30 and 45 degrees, so the slope here was right in that range.

There is also the crown or crown line, which is the upper fracture line of the slab that broke away to create the avalanche, as well as the flank or fracture line along the side of the avalanche.  There is one on the other side, although I have not labeled it.   


Most avalanches that kill people are slab avalanches in which a cohesive layer of snow slides down the slope.  Indeed that was the case here with the slab sliding about 20 inches or 50 cm down the slope as a cohesive layer.  In this case, the length and speed of the avalanche was such that the slab remained intact.  However, eventually it encountered the lower angle sidewalk where the slab decelerated, debris built up, and the toe of the avalanche was found.  

The bed surface for this avalanche was the grass rather than a weak layer in the snow.  The trigger was likely solar heating, which led to a lubrication of the grass by liquid water as the snow melted, weakening the bond between the snow and the grass.  Such an avalanche is referred to as a glide avalanche, which is defined as a release of snowcover as a result of gliding over the ground.  

So much snow science in such a small space!  However, there are real-world applications.  Glide avalanches can be deadly and destructive.  In the Wasatch Range, they are probably most common in Broads Fork, a subdrainage of Big Cottonwood Canyon where glide avalanches commonly occur on steeply sloped rock slabs.  Here's a link to a report about one in Broads Fork: https://utahavalanchecenter.org/avalanche/69596. Note the fully exposed rocks in the starting zone of the avalanche.  

Glide avalanches are hard to predict, but can have deadly consequences.  They are also common in the Alps where the mountains are not only steep, but there are a lot of grassy, high altitude meadows that are grazed in the summer.  The resulting steep, grass slopes can make the perfect bed for an avalanche.  I saw the aftermath of many glide avalanches when I lived in Innsbruck, Austria.  Below is a photo looking down at one during a ski tour on the Gammerspitz, a 2500 meter peak in the Alps south of Innsbruck.  It was on a south facing slope and likely was triggered by solar heating like the avalanche I saw today in the Avenues.  We avoided slopes like this on our tour! 

I found the number of glide avalanches and the expansive coverage of glide cracks in the Alps to be very disconcerting and often made conservative terrain choices because of them.  Fortunately it was easy to avoid avalanche terrain today in the Avenues.

It Shall Get Warm

It's sort of weird after a winter with little valley snow to look out the window and see what might be the deepest snowpack of the season in my yard.  Admittedly, "deepest" in the valley this year is a low bar, but it will be good for the gardens eventually.  It was a wonderful storm for skiing too.

I can summarize the forecast for the next several days in two words: warming trend. Oh, today will be a cloudy "meh" day and Friday night and Saturday we'll have a trough passage that could bring a bit of snow, but after that a big ridge builds into the west.  Below is the GFS forecast valid 0000 UTC 27 March (6 PM Wednesday) showing the high-amplitude ridge parked just upstream of Utah.  

The NWS National Blend of Models maximum temperature forecast for Salt Lake City shows the warming trend nicely after Saturday, with temps climbing through Thursday.  


The median maximum temperature forecast for Thursday afternoon is 81°F, which would be the earliest 81 on record.  I thought this NBM forecast seemed a little jacked, but mid 70s seems doable.  

Bottom line: It shall get warm.


Monday, March 17, 2025

Another Spring Cold Front

The weather yo-yo of spring continues today and tonight with the approach and passage of a spring cold front.  

The 6Z GFS shows the cold front moving across northern Utah tonight at 0600 UTC 18 March (0000 MST Tuesday). 

Ahead of the front, today will be mild and windy with the possibility of blowing dust.  The prefrontal environment today looks to be mainly dry, although I wouldn't be surprised to see a spritz or two of valley rain or mountain snow.  Precipitation is not expected for the evening commute.  

The front drags through tonight.  Onset time, duration, and accumulations for the valley vary some from model to model.  For brevity, I'll focus here on the 1200 UTC initialized HRRR.  The time-series below is for the Salt Lake City International Airport.  Precipitation onset is just before 11 PM local time, but the turnover to snow doesn't occur until after 2 AM.  I'm not sure if I'd count on that timing given the uncertainties at play, but expect precipitation to move in tonight and at some point to turn over to snow at all elevations.  

The HRRR produces a bit under 3 inches of snow at the Airport by 8 AM tomorrow morning.  Bench accumulations would likely be greater.  Below is the NWS infographic for this event showing the expectation for 1-3" for the Salt Lake Valley floor and 2-6" for the benches.  

NWS infographic downloaded 9:30 MDT 17 March

For the mountains, I suspect Tuesday will be a pretty good powder day, but you didn't hear that for me.  

Wednesday, March 12, 2025

Winter Begins (LOL)

We really haven't had much of a winter this year in the Salt Lake Valley.  Snow has been scant (only 12.7" through yesterday, the 3rd lowest on record through that date) and temperatures mild (7th warmest mean temperature on record through yesterday). 

It's been sunny and mild the past few days, so it definitely feels like spring.  Things will change late tomorrow with the passage of a cold front.  A couple of days ago I was going to call it the Start of Winter for the valley, but the storm is splitting and right now not looking as large as I thought a couple of days ago, although it could still have impacts. 

The GFS forecast valid 0000 UTC 14 March (6 PM Thursday) has the front and frontal band moving through northern Utah.  


Frontal passage at the airport in the GFS occurs at about 2200 UTC (4 PM Thursday) and the HRRR about 000 UTC (6 PM Thursday) so expect it to get here in the late afternoon to around dinner time.  Pre-frontal conditions will be windy and mild, with perhaps a few valley showers or maybe a thunderstorm.  Temperatures and snow levels will drop rapidly behind the front, with what looks to be a brief period of heavy snow to the valley floor.

Below is a time series for the Salt Lake City International Airport from the HRRR that includes our machine learned snow-to-liquid ratio and snowfall amount forecast.  Yes, it is possible to produce these for anywhere in the continental US on weather.utah.edu if you know where to look.  One can see the frontal passage at around 6 PM with the drop in the height of the 0.5C wet-bulb level.  Precipitation also picks up at that time.  Precipitaiton with the front persists through about 9 or 10 PM (although it's light( and then there is another brief period in the early morning hours associated with some HRRR lake effect.   


Snowfall with the front adds up to a bit more than an inch and then the lake band adds another inch or so, although that's a relatively low probability possibility.  

I think it's worth keeping an eye on official forecasts tomorrow for the evening commute.  A brief period of heavy snow with post-frontal wind can make things nasty quickly, although perhaps the warmth of the roads will help stave that off some.  A lot will depend on intensity and duration and perhaps elevation.  I took a look and the official NWS forecast is for 1-2" at the airport and a bit more on the bench, which makes sense to me.  Their forecast discussion expresses similar concerns to mine above: "A rapid changeover to snow could bring some impacts to the Thursday afternoon commute."

Monday, March 10, 2025

Good News for Skiers and Water Managers

A spectacular early March weekend is now in the books.  For skiers and water managers, March is an important month.  The spigot can stay open, extending the powder season while there is a deep snowpack and delaying the spring runoff (often leading to a more efficient runoff), or we can transition to spring conditions with the snowpack suffering a slow death.  

If you are a skier or a water manager, I think you will like the extended forecasts.  For the early part of this week we'll have our share of warmth, sunshine, and spring fever, but the models are calling for a major shift later this week to a more active pattern with a parade of troughs moving across the western United States thereafter.  

It's a long-enough range forecast that I don't want to talk about details, so I'll summarize with the Utah Snow Ensemble plume for Alta. It's flatlined for water equivalent and snow until late on the 13th when thigns really start to pick up.  There are some big numbers thereafter.  The driest member pumps out 1.63" of wter and 23" of snow through 0000 UTC 20 March (6 PM MDT 19 March), which is more than what we would expect over a 6 day period based on climatology (or average).  

Most of the members are between 2.25 and 4.5 inches of water and 30 and 60 inches of snow.  That would be an impressive storm cycle for mid-to-late March.  There will be breaks in the action over that stretch, so don't assume it will snow continuously, but right now it looks like a series of storms will bring the goods.  

Saturday, March 8, 2025

Adios X

After more than a decade of engagement on Twitter/X, I departed from that platform yesterday.  

The post prompted people to ask if I was Ok or if I was leaving the U, but I was merely leaving X.  It is a wonderful platform for sharing weather and science information but for some time the meanness and cruelty there have worn on me.  The nonstop bombardment of click bait was affecting my mental health. Enough was enough.  You can find me on Bluesky for now (@professorpowder.bsky.social), although I'm not going to be on it as frequently.  

Thank you for keeping this blog a place where science, weather, and snow are discussed respectfully.

Thursday, March 6, 2025

Problems I Want to Work On

Last night's storm period was one that I really enjoyed simply because it shows how remarkably variable snowfall can be in the central Wasatch.  As suggested in the prior post, the low-level ESE flow favored Deer Valley, which received more snow than Alta-Collins.  

Deer Valley/Ontario: 1.41"/14+" (snow depth sensor got flaky at 7:35 AM; 14 was the total at that time)
Alta-Collins: 1.02"/10"

It seems that a lot of data is not flowing into MesoWest from there resorts right now so I couldn't dig much deeper than that, but the Utah Avalanche Center report included storm totals as of 5 am also showing the decrease in snowfall from east to west. 

Source: https://utahavalanchecenter.org/

This is not something that is unusual for such a flow pattern or that experienced meteorologists wouldn't anticipate, as illustrated by yesterday's blog post.  However, we don't have a good understanding of the physical processes operating during such storm periods, nor do we have models that reliably anticipate such fine-scale snowfall variations.  By reliable, I mean not getting it right every now and then but instead being able to do it consistently. 

This has been the most challenging academic year of my career.  I'm not getting any younger and it has me thinking about what I want to do in my last few years as a researcher.  During my career, I have always been interested in snow and I'm especially interested in understanding and predicting microscale variations of snowfall in areas of complex terrain.  

Last night's case is a good example.  What I wouldn't give to have had a portable radar in the Heber Valley to see what is happening to the cloud and precipitation system on the south side of the Deer Valley Ridgeline and over the Snake Creek area southeast of Brighton.  It would have been so exciting.  More importantly, I'd like to compare this storms to others, as we all like to generalize, but the reality is that there are a lot of variations that we can't anticipate.  

Additionally, what I wouldn't give to have the time and horsepower to improve fine-scale forecasts of these storms using traditional numerical weather prediction or newer Artificial Intelligence/Machine Learning prediction systems.  

The reality is that we do not currently have a high-resolution ensemble that can reliably predict these fine-scale snowfall variations.  If you think the HRRR can do it, think again.  Here's the forecast from yesterday morning's HRR through 1200 UTC 6 March (5 AM today).  The numbers for Deer Valley and Alta-Collins aren't bad, but note how the snowfall maximizes not on the Deer Valley ridgeline but instead on the Alpine Ridgeline near Lone Peak.  We don't have observations up there, but I think that's an unrealistic spatial pattern.  

In part, this may be due to the resolution, or the grid spacing of the HRRR, which is about 3 km, or possibly due to how it deals with cloud processes, including the growth and transport of snow in storms.  The swiss aren't running models at 3 km grid spacing.  They are running them at 1 km grid spacing and trying to get even finer.  That might help.  However, one also has to be able to handle the snow growth, transport, and fallout processes right and this is where observations and clever minds are needed to incorporate such effects into our modeling systems.  

AI/ML is pretty exciting and is going to become increasingly important moving forward, but it's unclear how to do it for such fine scale precipitation patterns in which training datasets are limited.  There are some proposed approaches, but it's going to take careful testing and evaluation to advance AI/ML capabilities for situations like this.  

I guess in the end things haven't changed much throughout my career.  I love snow and winter storms in complex terrain and these are the kinds of problems that I want to work on.  Beyond my own personal interests, advances in these areas would likely help with forecasting for the 2034 Olympic Winter Games, road weather and avalanche mitigation in Little Cottonwood Canyon, and other weather and climate applicatios over northenr Utah.  

Wednesday, March 5, 2025

A Big Spring Storm

The model runs are pretty spicy and exciting this morning with a significant storm moving later today.  The latest GFS suggest precipitation beginning in the central Wasatch this afternoon or evening and continuing into Friday.  Let's have a look.  

The GFS forecast valid 0600 UTC 6 March (11 PM Wednesday) shows that the early part of the storm is characterized by an deep upper-level trough (upper left panel below) with a lower-tropospheric cyclone (red L in images below) over Nevada.  Associated with this system is an inland penetrating atmospheric river  atmospheric river that approaches northern Utah via the lower Colorado River Basin.  The crest-level 700-mb flow (lower left panel) is southerly or even south-southeasterly in the vicinity of the central Wasatch with 700-mb temperatures near -5°C.

Thus, the overnight storm period has all the hallmarks of a warm, high-density storm period.  Through 9 AM tomorrow morning, the GFS generates 0.77" of water and 8.2" of 10% water content snow. The HRRR is even more excited with water with 1.65" of water and 13.8" of 12% water content snow.  And that's just the start.  For the Wasatch Back crowd, that little bit of easterly flow gets my attention and suggests this could be a period where  you do pretty well.  This could be a period where snowfall is greater at Deer Valley and less at Snowbird, but we'll see if that pans out.  

The GFS drags the main cyclone very slowly across our area, resulting in a prolongued period of moist southerly to southwesterly flow that continues through the day tomorrow,  By 0000 UTC 7 March (5 PM Thursday), the storm is so wrapped up that we actually have cooler air moving into northern Utah from the southwest, as illustrated by the 700-mb (crest-level forecast at lower left).  By this time, the AR has moved downstream, but there's fairly deep instability and it's March, so things might get a bit convective tomorrow afternoon.  

I'm not sure if we might get a break in there for a bit as sometimes there can be a dry slot that sets up in a pattern like this, but by and large I suspect we'll see periods of snow tomorrow that will continue to stack up.  

Eventually the system moves through and we get into colder, unstable, northwest flow for Friday.


I've summarized the storm phases in the time-height section below.  Time increases to the left.  First there is the warm and juicy AR period Thursday night.  Note the low-level southeast flow that might favor the eastern side of the central Wasatch.  Then on Thursday, colder air wraps around the system and moves in aloft from the south and southwest.  Call it an upper cold front if you like, but it will destabilize things.  Temperatures drop further on Friday evening with a transition to colder, post-frontal flow.  


For Alta-Collins, storm totals in the GFS through 7 PM Friday are 1.77" of water and 24.1" of snow.  Expect that to be high density snow to start and lower density Thursday night and Friday.  The HRRR only runs through 5 AM Friday but it has 2.22" of water and 20.2" of snow.  It's less bullish on the post-frontal period whereas the GFS produces snow more continuously through the period.  Such model inconsistencies are one of the joys of being a meteorologist!

I'm inclined to go for a storm total of 1.5-3" of water and 20-36" of snow for Alta-Collins through Friday evening.  There are uncertainties in timing and details, but this looks like a pretty good storm.  The early part could be a big producer on the Wasatch Back.  It's a warm storm and perhaps snow levels will flirt with the lower Jordanelle/Mayflower area during the atmospheric river phase tonight and early tomorrow.  At upper elevations, I suspect the snow will be fairly dense everywhere before trending drier late Thursday and Friday. 

Buckle up and monitor forecasts.  There's a lot of moving parts in this storm.