Wasatch Weather Weenies

The University of Utah's Annual Giving Day is this Tuesday and Wednesday March 1st and 2nd.  Yes, I know that's two days and that we are a system of higher education that should be able to do math, but it is my understanding that Giving Day is 1850 minutes long rather than 1440 because the U was founded in 1850 and it is a Founder's Day Celebration.   If you are a fan of this blog, please consider making a donation.  The first $2,700 in donations for Atmospheric Sciences Scholarships will be matched 1:1 by department faculty, including myself, and my colleague Ed Zipser will throw in another $5,000 if we hit that mark.  To donate for scholarships, go to this link , select "Give", and choose "Atmospheric Sciences Scholarships."   Donations to other college scholarship funds also appreciated! Alternatively, you can give to our mountain meteorology fund at this link .  That's a persona favorite of mine and very relevant for this blog.   If ...

February is almost in the rearview mirror and it looks like we will enter March with snowpack across most of the western U.S. at or below median levels.  Below is the latest as of end-of-day February 24.   The "fattest" snowpack relative to climatology is in the Northern Oregon Coastal Mountains at 131%, although this is an area that actually does not rely much on spring snowpack melt for runoff, so that number isn't all that relevant.  There are 8 additional basins between 100 and 109% of median.  The rest are below and many are below 90% of median.     Source: NRCS In northern Utah, the Jordan, Weber, Lower Bear, and Upper Bear sit at 76%, 73%, 78%, and 82% of median.  The Jordan covers most of the creeks that emanate from the Wasatch Range east of Salt Lake City.  Average snowpack water equivalent at SNOTEL sites in the Jordan sits today at 11.2" of water, compared to a median for the date of 14.9".   Source: NRCS That's a d...

Apparently my excitement for everyone in Park City was irrational exuberance.  Despite easterly flow overnight, things never really lit up over there and snowfall amounts since 5 PM yesterday appear to be in the paltry 2-4" range.  Painful. Get out and enjoy the cold weather and snow scraps we get between now and Friday.  Ridging returns for the weekend.  A system brushes by Sunday night, although it currently looks dry, then ridging again for at least the first half of the work week.  You've seen this movie before.   From a water and snowpack perspective, we've barely bent up the flatline this week.  It will take a monster March now to get back to median.   There's always hope...

How about that.  It snowed.  Alta-Collins came in with about 7" through this morning, including 4" yesterday morning and afternoon and 3" overnight.  By historical standards, it ain't much, but we can't be choosy anymore.   The next trough swings through tonight and tomorrow.  It's a deep and complicated system as it swings across Utah.  Below is the GFS surface forecast valid at 0900 UTC 23 February (2 AM MST Wednesday).  The surface low is in southwest Utah with a fairly strong warm front extending across southern Utah and a trailing cold front across Nevada.  The flow in northeast Utah is predominantly easterly.    This general pattern extends to 700 mb (10,000 feet). Model soundings show a very sharp transition to southerly flow above 700 mb.  Below is the sounding from Salt Lake City.  Easterlies extend right to 700 mb, above which the flow veers (turns clockwise with height) to southwesterly. These conditions are con...

As I write this at 9 am on Sunday morning, it's been a beautiful holiday weekend so far.  Alta's Superior web cam shows sunny skies currently, but some high clouds to the west that will eventually spread over the area during the day in advance of an approaching upper level trough and cold front.   Source: Alta As discussed previously, the models continue to favor a solution with the cold front weakening near the Utah-Idaho border and then redeveloping over central Utah.   Below are GFS forecasts to illustrate this point.  Each includes color fill of 3-hour accumulated precipitation in inches based on the scale at the right. For the 3-hour period ending at 0300 UTC 21 February (8 PM MST Sunday), the front produces a continuous band of prcipitaiton from northern Nevada into southeast Idaho.  It certainly looks good.   However, the front falls apart as it enters northern Utah.  For the 3-hour period ending at 0900 UTC 21 February (2 AM MST ...

Wednesday's expectation exceeding storm notwithstanding, we desperately need snow.  The Jordan and Weber River Basins now sit at about 75% of median snowpack. This is no longer a matter of skiing quality, but becoming deeply concerning for water-resource availability this summer and fall.   Our next shot at snow is Sunday night through Tuesday.  This is a gut-check forecast if ever there was one.  There has been a lot of talk about pattern changes for the past few weeks.  The storm for Sunday night through Tuesday does not reflect a major pattern change, but a slight shift upstream (westward) shift in the position of the upper-level ridge that has produced our dry spell.  This has shifted the track of troughs in the northwesterly flow east of the ridge a bit westward.  While that gives us better shot at snow, these troughs tend to be splitters, greatly increasing the forecast complexity and range of possible outcomes.  Here's the forecast fro...

The holding of a Winter Olympics in a region that gets very little snow has cast a media spotlight on Olympic snowmaking and climate change.  Especially attention grabbing has been the Yanqing Alpine Venue where, until a small storm a couple of days ago, featured ribbons of artificial snow covering the courses.  The lack of natural snow at that venue really makes the extensive use of artificial snowmaking stand out.  Media reports suggest that a million cubic meters of water was used for snowmaking for Beijing .  I wanted to check that number and dis some searching.  The Beijing 2022 Pre-Games Sustainability Report estimates that the total water demand for the Winter Olympics (November to March) in the Yanqing Zone Venues was estimated to be about 890,000 cubic meters and and for the Zhangijakou Zone Venues is 1.9 million cubic meters.  These numbers include all water consumption.  For the Zhangijakou Zone, the 1.9 million cubic meters includes 730,00...

Avalanche debris above Innsbruck, Austria in Spring 2019.  This is the second of two posts exploring how climate change will affect avalanches, based in part on a recent paper by Strapazzon et al. (2021) in Frontiers in Physiology .  In the previous post , we examined the influence of climate change on the weather and snow characteristics of mountainous regions, emphasizing elevational- and seasonal-dependent trends.  Let's begin with a summary of some of the most relevant for avalanche dynamics and severity: Declines in snow cover duration and depth are likely and could be large at lower elevations (for high-emissions scenarios), but trends for upper elevations are smaller or in some areas less clear (especially for low-emissions scenarios) Snowfall intensity may increase, especially in colder upper-elevation areas that serve as the starting zones for major avalanches. Temperatures will increase, resulting in higher snowfall densities, more mid-season melt events, and mo...

I get a lot of questions about climate change that don't have a simple answer.  As the saying goes, the devil is in the details and the answers to climate change questions are not easily generalized.   Perhaps the hardest are those pertaining to the effects of climate change on avalanches.  There are many ways that weather, snowpack, and terrain affect snowpack and there are many types of avalanches.  Climate variables that affect avalanches include temperature, cloud cover (and its effects on solar and long-wave radiation), humidity, wind, precipitation type (rain or snow), precipitation intensity, and precipitation frequency.  The influence of each of these can vary with elevation and aspect.  Beyond the effects of greenhouse gases on climate, dust and black carbon due to land-surface disturbance or fossil fuel combustion can have a strong impact on the snow.  Finally, avalanches need a natural or human trigger and, when it comes to the latter, ...

Sadly, there was no Steenburgh winter this year, that period from when Alta-Collins reaches a 100" snow depth to 10 February when day length and solar angles start to increase rapidly, with the sun having an increasingly caustic impact on the snow.  Peak snow depth at Alta-Collins was 97 inches in early January, so we were close, but close is not close enough for the snow snobbery that we promote on this blog.   Thus, spring begins today.  You're probably already noticing the sun rising earlier and setting later.  Maybe you'r noticing the sun more on slopes that were often topographically shaded in December (Collins Gulch I'm thinking of you).   I continue to monitor the medium-range forecast.  It's not changing a lot on the large scale.  The ridge over the northeast Pacific continues to dominate, with out best hope being troughs that drop down into the western US from the northwest. The next one is forecast to be affecting Utah on Tuesday....

It's been interesting watching social media feeds the past couple of days and all of the comments about the snow conditions at the Yanqing Alpine Venue in Beijing.  The lack of natural snow at the venue, which is consistent with the dry wintertime climate of the region, has very much highlighted the role of artificial snowmaking in the Olympics.   However, claims like the one below that there's something unusual about the snow surface and that it is a problem for Alpine ski racing are simply not accurate.   The reality is that Alpine ski racers prefer a hard, icy, durable snow surface.  In a recent study, athletes and coaches were asked to rate the influence of 23 weather/snow conditions on performance, fairness, safety, and overall impact on a scale from ideal to unacceptable.  Conditions rated closest to ideal were hardpack snow, injected surface (this typically means a snow surface injected with water, which freezes and makes it harder), ice, and ma...

 Beijing China is 15 hours ahead of Salt Lake City and 8 hours ahead of the Coordinated Universal Time (UTC) used widely by forecasters.  The former means that you can watch morning and early afternoon events from the next day before going to bed and the evening events from that day on delay when you get up in the morning.   The past two nights I've watched some of the training for the Men's Downhill.  There are multiple story lines here.  Let's begin with the venue, the Yanqing National Alpine Skiing Centre.  I visited it in 2018 as part of an educational meeting on Olympic weather monitoring and forecasting.  It was in the early stages of construction.  It certainly looked to have the vertical and steepness needed for a decent Olympic downhill, but prior to the building of the resort, the area was largely undeveloped.   We were told that it the resort averaged 25 inches of snow a year, but it is possible that was 25 cm (about 10 i...

Each ski season is unique in its own way, but I have reached a point meteorologically and physically where it is clear that this will be a two-part ski season.   Part I was from mid-October until mid January.  It was a herky jerky period. Snow in October and early November, followed by drought into mid December, followed by snow until early January.  There was some good skiing and some not-so good skiing, for a time primarily on upper-elevation north-facing aspects.   The December storms opened things up for ski touring, Nordic skiing, and resort skiing.  Skiing fun in all its forms. The spigot closed, however, in early January.  I didn't realize it at the time, but the snow season and my ski season would pivot on January 7.  Through that date, Alta had recorded 254.5" of snow.  Since then, they've had less than 10 inches.  Additionally, I woke up that morning with a sharp pain in my upper foot.  I had skate skied the prior day...

A little lake-effect action last night has made a mess of the morning commute. It's been a while since we've had this much valley snowfall, so let's take a look at what happened.  On the large-scale, there was a weak trough passage that occurred early this morning.  This trough was accompanied by deep instability and moisture, with precipitation enhanced over the Great Salt Lake.   This transition is clearly seen in upper-air soundings from the Salt Lake City International Airport.  Yesterday afternoon it was well mixed in the lowest levels with a 700-mb (10,000 ft) temperature of -17˚C.  However, the sounding was also fairly dry and it was absolutely stable in the mid levels above 700 mb.  Thus, conditions were not favorable for the development of deep precipitation clouds, although you could find a few snow showers from shallow clouds in the mountains.   This mornings sounding is only slightly colder at 700 mb (18˚C), but is much colder in ...