Monday, March 30, 2015

March Goes Out Like A Furnace

The last two days of March look to be warm and toasty by climatological standards as we get the warm southerlies ahead of a cold front that is expected to push into northern Utah late Tuesday.

NAM 850-mb wind, temperature, and 3-h precipitation forecast valid 6 PM MDT 31 March.
Yesterday's high at the Salt Lake City airport was 66ºF.  We'll tack some more onto that today with a high of about 74ºF.  Unless the front comes in faster than currently suggested by the models, it looks like a max in the high 70s tomorrow.  I give 80 a 20% chance (The NWS is going for the big 80).  The records are 77 and 80 for today and tomorrow, respectively.

The warmth, however, will give us a shot for the warmest March on record.  So far, we've averaged 49ºF, tied with 2012 and 2014, and just behind 1992 (49.2), 1934 (49.2), 1910 (49.6), and 1879 (49.2).   
Source: NOAA Regional Climate Centers
Can we top 1910?  Assuming a low last night of 40, a high today of 74, a low tonight of 49, and a high tomorrow of 78, we'd have a monthly average temp of 49.7—just enough to top 1910 by 0.1ºF.  It's gonna be close.  

In case you are wondering, the all-time Dec-Mar record for the airport is safely in the bag.  We are currently ahead of 1978 and 1934 and will add to that lead today and tomorrow. 

If you are tired of the heat, Wed–Fri looks much cooler, although a big mountain snowstorm looks unlikely.  

Sunday, March 29, 2015

City Creek Melt Out About a Month Ahead of Schedule

It's been a beautiful weekend, providing some gorgeous views of City Creek Canyon.  The snowpack, however, is quite minimal with nary a patch of snow to be found except on the upper elevations of Grandview Peak.

There are actually three SNOTEL stations in or near City Creek Canyon allowing us to get some idea about how this year compares to others.  The lowest is the Louis Meadow SNOTEL (6700 feet).  There must be a few patches of snow remaining in the lower canyon that can't be seen in the photo above as it is still registering a couple of inches of snow water equivalent (blue line).  This is about the equivalent of the median snowpack (red line) in late April.  

The Hardscrabble SNOTEL is at 7250 feet behind Grandview Peak in this photo.  It too is running perhaps a month (or a bit more) ahead of median.   

Finally, the Lookout Peak SNOTEL (8200 feet) hasn't yet begun to experience significant snowpack loss yet, but the equivalent median is in mid May.  

SNOTEL stations tend to be located in sheltered areas that retain their snowcover better than the south aspects viewed in the photo above.  Nevertheless, one gets some idea of the unusual nature of this spring...not that any of you who live in northern Utah are surprised!

One thing that really got my attention today was emergence and and breaking of buds on the scrub oak.   

It's my anecdotal impression that the scrub oak are rarely in a hurry to bud.  I wonder what the typical time of bud break is for this native species.  Anyone out there know?

Enjoy the nice weather the next couple of days.  Colder weather looks to be on the way midweek.

Friday, March 27, 2015

"These Glaciers Are Dying"

Lonnie Thompson presented a remarkable portrait of climate change as inferred from high-altitude tropical glaciers at last night's Frontiers of Science lecture at the University of Utah.  Aspects of the presentation that really got my attention include the following:

1. Ice cores from glaciers and ice caps provide a remarkable history of climate change extending back in some cases 800,000+ years (Antarctic ice).

2. The loss of glacial ice in the tropics is accelerating.  The race is on to obtain and preserve cores from these areas.  One of the figures presented by Lonnie derives from a recent paper by Cullen et al. (2013) who used photographs and three-dimensional visualization techniques to map the remarkable loss of ice on Mt. Kilimanjaro from 1912 to 2011.  
Source: Cullen et al. (2013)
The figure above emphasizes changes in glacial area, but there is also thinning.  Together, this results in a significant decline in ice volume.  Basically these glaciers are dying from the sides and from the top down.  This is happening across the tropics including in Papua New Guinea and the Andes (a comprehensive summary of the latter available here).

3. 98% of the worlds glaciers are currently losing mass.  Those on Papau New Guinea will likely be gone by the end of the decade.  Roughly half of the glacial ice the the alps will be gone by 2040.

I first saw Lonnie speak 10 or 15 years ago.  The changes he was documenting back then were impressive, but those described in this latest talk are jaw dropping.  Change is underway and it is starting to pick up speed.

Lonnie also shared a remarkable story.  A leader of more than 50 high altitude expeditions for scientific research, he was stricken with congestive heart failure.  He is now a heart transplant recipient.  Learn more about Lonnie's remarkable research and life in this New York Times article by Justin Gillis.

Thursday, March 26, 2015

Collins Gulch vs. Supreme: Which Is Snowier?

With no major storms in sight, we turn our attention today to the next most important question on skiers' minds.

Is it snowier in Collins Gulch or the Supreme area at Alta?  I've always argued for the former, but I know many that argue for the latter (this is for total seasonal snowfall—the winner sometimes varies within individual storms).

This fall, my students installed one of our low impact weather and snow measurement stations at 9603 feet in upper Albion Basin (special thanks to the cabin owners who are hosting the equipment) at a site we call "Top Cecret" since it is near the top of the Cecret chair (and thus in the Supreme area).  The idea was to get some experience operating this equipment in a deep snow environment. We were hoping for some challenges.  Tripods are best used in no snow or lower snow environments.  In deep snow environments, you run into two issues.  One is that the creep of the snowpack can mangle the tripod.  The other is that as the snow depth increases, at some point you need to take off the equipment, add an extender, and then remount the equipment.  That's a job that's time consuming but not too difficult in nice weather, but isn't a heck of a lot of fun in the cold.

This winter none of that has mattered as we've had the worst snow year since WWII.  As of last weekend, the tripod bases were well buried, but the observing equipment was still far enough above the snowpack to be operating effectively.

Our comparison site is the Alta-Collins snow-study station expertly maintained and operated by Alta Ski Area at 9662 feet in Collins Gulch.  This station has provided timely and reliable observations of snowfall and snowfall water equivalent for many years, greatly assisting weather forecasting and research efforts in Little Cottonwood Canyon.  

Both Top Cecret and Alta-Collins are equipped with ultrasonic snow-depth sensors that send out inaudible pulses of sound and infer the snow depth based on how long it takes for the sound to return to the sensor.

What are the current snow depths at the two sites:

Top Cecret: 82 inches
Alta-Collins: 77 inches

Looks like Supreme is the winner!

Not so fast.  These are two localized measurements of a highly variable snowpack.  We really can't make any strong conclusions one way or the other and perhaps there simply isn't a major contrast in snow between the two areas.  Let the debate rage on.  What think you?

Wednesday, March 25, 2015

Cloning or Time Travel Recommended

If you are interested in climate science and policy, there are two great opportunities for learning more tomorrow (Thursday) at talks being given in Salt Lake City.  They overlap, so clone yourself or get a time turner and get to both.

Thursday, March 26
Dr. Lonnie Thompson
Frontiers of Science Lecture
"Global Climate Change, ENSO and Black Swans: A Paleoclimate Perspective from the World’s Highest Mountains”
6:00 – 7:30 PM
220 Aline Skaggs Building
University of Utah

Dr. Lonnie Thompson.  Source: The Ohio State University
Thursday, March 26
Dr. Katharine Hayhoe 
7:00 to 8:00 pm
Clark Planetarium, 110 S 400 West, SLC

Dr. Katherine Hayhoe.  Source:

Tuesday, March 24, 2015

Looking Back, Looking Forward

Yesterday evening, there were a few fireworks in the Salt Lake Valley, but you might have missed them if you blinked.  Some stronger cells popped up near the south shore of the Great Salt Lake just before 8 PM MDT and I saw a lightning flash or two during this period.

The band along which these cells formed moved southeastward and, although weakening, gave a final blast of snow to the central Cottonwoods.

If you are going out skiing today, I suspect you will find a large increase in snowfall from 8000 to 9000 feet.  Accumulations at 8500 feet and above in upper Little Cottonwood look to be around 6 inches.  The Big Cottonwood resorts are reporting a bit more.  At Solitude, my bet is the 10 inches they are reporting is for the summit and you'll find a lot less at the base.

A quick hitter late today through about midnight will lay down a couple more inches in the mountains and some valley showers, bringing to an end our brief flirtation with spring showers.  After that, the death ridge returns.

Monday, March 23, 2015

A Brief Flirtation with Spring Showers

Every couple of weeks Mother Nature allows a storm or two to slip through the net and give us a brief break from the death ridge.  One of those storms is here this morning as a cold front is sweeping across northern Utah bringing valley showers and mountain snow showers.  We'll then have a break later tonight and Tuesday, with another front coming in Tuesday night, after which the death ridge returns.

Two fronts sounds exciting, but this really isn't a major storm cycle by old-fashioned Utah standards. In the upper Cottonwoods, the NAM is generating about .3 inches of water and 4 inches of snow today and tonight, with another .2 water/2 inches of snow with the front on Tuesday night (see lower two panels below).

My usual approach in the winter is to use the NAM as the low-end of the forecast range for Alta, but such an approach doesn't typically do as well in the spring when storms on average feature less orographic enhancement.  In addition, this looks like a pattern where showers will be hit or miss.  In other words, if you don't like the weather, wait 5 minutes.  As such, I think a total of 3-6" today and tonight is probably reasonable, although I won't be surprised if we come in a bit below or above that given the showery nature of the pattern.  Yes, there is a chance of thunderstorms too, which would make may day.  Looks like rain for the valley, unless we get a very strong shower and then perhaps we'll mix in some graupel or ice pellets.

We'll get a little more with the second front.  Maybe in total the two events will give us something in the 5-10 inch range in the upper Cottonwoods.  Not much by old fashioned standards, but a blizzard by contemporary standards...

Sunday, March 22, 2015

Has There Ever Been a Snow Season Like This?

Photos of Mt. Superior from Alta Ski Area show the two extremes of the Wasatch snow climate on 11 June 2011 (a season with about 800 inches of snow at 9500 feet and cold weather deep into the spring) and 21 March 2015 (a season with about 250 inches of snow - so far - at 9500 feet and record warmth.  
The answer is probably not during the period of reliable snow records at Alta-Guard, which begin after WWII, but there are a few nuances to consider, especially with regards to snowpack. 

What we know is that this winter the Dec-Feb period was the warmest on record (since 1895) in the northern mountains climate zone that includes the Wasatch and Uinta Mountains.  The closest analog in the instrumented record is 1933/34, but that was before reliable snow records at Alta-Guard.  The only other Dec-Feb period with temperatures close to this winter is 1980/81.  More on that season in a minute.

Source: NCDC
What about March?  Well, the temperature records for this March are still trickling in from volunteer observers.  Through yesterday, though, we were running well above average.  In terms of where we were through from December through the end of astronomical winter on Friday, there's a good chance it was the warmest such period on record.  

With regards to snow, the Utah Avalanche Center reports that Alta-Guard has has had only 213.5 inches of snow since November.  It looks like we're going to get some snow Monday-Wednesday.  I'm not sure how much, but for the sake of argument, let's suppose it goes big and we end up with 250 inches through the end of March.  The only other winters with less than 300 inches from November –March are 1960/61 (291 inches), 1962/63 (265 inches), and 1976/77 (283.5 inches).  Let's also throw 1980/81 into the mix since it is the closest temperature analog.  In that low snow year, the November–March snowfall was 339 inches.  

But let's look at the March snowfall in those years specifically.  In 1960/61, 1962/63, and 1976/77, and 1980/81, the March snowfall was 113, 93, 129, and 110 inches, respectively.  These were drought years, but they rallied at the end, producing above average snowfalls in March.  That's not going to happen this year, even with the storms Monday–Wednesday. 

Thus, the combination of low snowfall and high temperatures for December to mid March appears to be unprecedented since record keeping began after World War II.  

However, we haven't looked at snowpack yet.  Ideally, one would look at manual snowpack water equivalent observations for which there are records at some sites in the Wasatch that extend back to before World War II.  I don't have easy access to those records, and often they are collected around April 1st, so I'm going to leave that as an assignment for you weather sleuths and instead look at shorter-term records from SNOTEL stations.  Unfortunately, these don't extend back to 1980/81, but they do go back to 1989 or so for most central Wasatch sites.  

At the Mill D North SNOTEL, the snowpack has already ripened and begun to melt (green line) this year, which is quite remarkable (green line).  We've already lost about 3 inches of water at this site to melt.  Curiously, the winter of 1991/92 has a peak snowpack water equivalent that is only slightly higher than this year, even though we are way behind in snowfall amount at Alta-Guard.  During that season, the Alta-Guard Nov-Mar snowfall was 367.5 inches.  More on this in a minute.  

The Brighton SNOTEL shows similar behavior, with 1991/92 also being the next lowest season.  

Now lets shift to Thaynes Canyon (Park City) and Snowbird.  Both of these sites are on north-facing aspects and thus the melt has yet to begin in earnest.  Again we see 1991/92 raise it's ugly head as the next lowest season.  In fact, snowpack water equivalent at Snowbird is right on top of that year as of Friday. 

So, we sort of have a mixed bag when it comes to snowpack water equivalent observations, although most are well behind 1991/92.  How to explain the snowpack observations, especially at Snowbird?  
Welcome to the world of observational uncertainty and the comparison of apples and oranges.  SNOTEL observations are affected by changes in site characteristics and instrumentation.  They are also a measurement at a single point and in any one season, wind transport and other factors can play a role. 

Such issues affect other observations we've used here.  For example, the Alta-Guard snowfall observations are affected by changes in measurement location or techniques.  In addition, we are comparing seasonal snowfall observations (the sum of new snow depth observations taken daily or even more frequently) as opposed to snow water equivalent observations.  The latter are more important for the snowpack.  It could be that we had a low snowfall year this year, but the water equivalent is not far behind 1991/92 (another issue for you weather sleuths to dig into).  

When I put all this together, I think it's pretty safe to say that the combination of warmth and snowfall for this winter are unprecedented since WWII.  It is possible (perhaps even probable) that the current Wasatch snowpack is probably about as low as it has been in mid March since WWII too, but I'd like to see some additional analysis of longer-term snowpack records to see where we stand overall.  Again, I appeal to you enterprising sleuths out there to dig into this problem further and provide comment.

PS: I would still take this year over 1976/77 which had very little snow in the early season with most falling late.  If you have to pick between snow early and snow late, the former is better.  Further, despite the low snowpack, groomers will still fun yesterday.  Plus, keep an eye on the storms for Monday-Wednesday.  Winter is returning. 

Saturday, March 21, 2015

1,000,000 Served!

Sometime yesterday morning, the Wasatch Weather Weenies hit 1,000,000 lifetime page views.

Our first post was on October 1st, 2010.  Initially, we were an invite only blog, but response was overwhelming, so I decided to open it to the public, trollers and all :-).  I'm so glad I did as it's been great fun writing for everyone.  Page views by month show that we pick up more readers each winter.  Where everyone goes in the summer I have no idea!

Our first winter was amazing.  Huge amounts of snow, lots of storms, and lots of skiing.  I logged 66 days of skiing that season, including 3 days on Mt. Rainier with my son around July 1st.  Ah, those were the days.

Since then, both snowfall and my back have been on the downswing, but we've found plenty to talk about anyway.  In case you are interested in looking back, here are the 10 most viewed posts.  A few of these have been boosted by people following Google searches for specific phrases or people.  Blogging about "Fabio" (#4) has greatly boosted my readership.

  1. Let's Rock, 25 April 2012
  2. Outlook for the 2013–14 Ski Season, 30 Aug 2013
  3. Tour de France Weather, 15 July 2011
  4. West to be Tickled by Fabio, 18 July 2012
  5. Powder Explosion!, 11 Dec 2013
  6. Bogus Snow Science, 30 Nov 2013
  7. The Untold Story of How Santa Claus Really Comes to Town, 23 Dec 2011
  8. Is This a Long Term Trend?, 7 Feb 2015
  9. The Approaching Mother of All Inversions, 13 Jan 2013
  10. Northern Utah's Christmas Miracle, 23 Dec 2014
If you've enjoyed the blog, consider clicking here and making a donation to the Mountain Meteorology Fund at the University of Utah.  Unlike McDonalds, our posts antibiotic and filler free.

To celebrate, I'm going skiing.  

Thanks for reading!


Friday, March 20, 2015

Projected Changes in Snowfall over the Western U.S.

An paper published last month in Water Resources Research, Lute et al. (2015) provide an interesting and insightful look at projected changes in snowfall and winter storms over the western U.S. through the mid 21st century (2040–2069) based on climate models run for the most recent IPCC Fifth Assessment Report.  They use statistical techniques trained with historical data to downscale these course-resolution climate model projections and obtain snowfall and winter storm trends at SNOTEL station locations across the west.  Not surprisingly, the results are fairly sobering for the skiers and lovers of snow.

To begin, we need to review the climatology of SNOTEL stations across the west.  SNOTELs are remote weather and snowpack observing stations used for a variety of purposes, but primarily water resource management and forecasting.  They tend to be located in sheltered locations and, within a given mountain range, typically at mid elevations (e.g., mid mountain Snowbird, but not at the summit).  The wintertime (Nov-Mar) average temperature at these SNOTEL stations tends to be higher in the Cascades, Sierras, and Arizona Mountains, and lowest over the high terrain of Wyoming, Utah, and Colorado.

Average wintertime (Nov-Mar) temperatures at SNOTEL stations.  Source: Lute et al. (2015).
The average western U.S. temperature and precipitation change from 1950–2005 to 2040–2069 for the climate models used by Lute et al. (2015) is summarized in the graph below below.  Most of the models call for 2–4ºC of warming between these periods, but there are a couple colder and warmer outliers.  Precipitation increases range from 3% to 18%.  The key point here is that there are a range of outcomes, which we will ultimately consider.

Source: Lute et al. (2015).
The average percent change in annual snowfall water equivalent (SFE, the liquid equivalent of snowfall) produced by the Lute et al. (2015) downscaled climate model projections for 1950–2005 to 2040–2069 is shown below.  The losses are greatest at relatively warm SNOTEL sites in the Cascades, Sierra Nevada, and Arizona mountains, in some instances > 55%.  As one moves to the interior where most SNOTELs are higher and the climate is more continental (i.e., colder in winter), the losses are smaller, although there are a few stations with a warm storm climatology like Ben Lomond Peak in northern Utah that experience larger loses.  At the coldest, high-elevation SNOTELs in Wyoming and Colorado, the decline is so small that it is not statistically significant (small circles) and it is unclear if such changes would be detectable given the large ups-and-downs in snowfall from year to year.  Keep in mind that the highest SNOTELs are at about 11,500 feet.  Perhaps above that elevation in Colorado they might have obtained a slight increase in snowfall.  
Source: Lute et al. 2015
Below is the trend for the number of snow days.  The pattern is fairly similar with declines everywhere, but largest at warmer sites and smaller at colder sites.

Source: Lute et al. (2015).
Although snowfall and the number of snow days declines, a more complicated picture emerges if you look at the average size of the largest 3-day snowfall events (the top 10% based on snowfall liquid equivalent).  Although there are declines in the Cascades, Sierra, and Arizona mountains, especially at warmer sites, the trends are either small or weakly positive at cooler, interior sites over Wyoming, Utah, and Colorado.

Source: Lute et al. (2015).
These results are broadly consistent with the expectation that storms become less frequent but of greater intensity in a warming world due to the higher atmospheric water-vapor content at higher temperatures.  At warmer sites, however, these bigger storms end up producing rain or mixed-precipitation, rather than snow, leading to declines.  At colder sites, these more intense storms will still be producing snow, hence a slight upward trend.

Those are the averages, but an important factor to consider is the range of model projections.  Lute et al. (2015) have a nice figure for showing this range by presenting the mean change in annual snowfall water equivalent (SFE), snow days, and the largest 3-day snowfall events within bins based on current average wintertime temperatures.  For SFE, declines increase with increasing temperature.  The most "optimistic" model is MRI-CGCM3, which calls for only about 1.5ºC of warming and about a 15% increase in precipitation, yielding a slight increase in wintertime SFE at the coldest sites and the smallest declines at warmer sites.  All the models, however, produce declines in the number of snow days, including MRI-CGCM3, consistent with a shift toward fewer, more intense storms.

Source: Lute et al. (2015).
Finally, the bottom figure above shows the change in the average size of the largest 3-day snow storms.  At the coldest stations they get bigger, whereas at the warmest stations they decline.  Perhaps Colorado will see an increase in deep powder days between now and mid century?

So what does all this mean.  To me this study reinforces the view that there is a temperature dependency of snowfall and that warmer locations in the Cascades, Sierras, and Arizona Mountains, are most vulnerable to the first few degrees of global warming.  At colder, upper-elevation sites, the changes in snowfall for the first few degrees of global warming are smaller and year-to-year variations in snowfall produced by climate variability may dominate over any long-term trend for some time (remember, however, that these results are strictly for snowfall and snowstorms, not snowpack).  However, we're looking here at changes through the mid 21st century so this isn't an end point.  In the long run, much will ultimately depend on future CO2 emissions and just how sensitive the climate is to greenhouse gas concentrations.  If you want to run this experiment out to a CO2 concentration of 1200 ppm, 4 times pre-industrial levels, good luck with that.

Thursday, March 19, 2015

Hot for Everyone Except the East

It has been a remarkable Dec-Feb (Northern Hemisphere winter/Southern Hemisphere summer) globally, regionally, and locally.  Globally, it was the warmest Dec-Feb period on record, eclipsing the previous record set in 2006/07.

Source: NCDC
For the Northern Hemisphere, in particular, it was a scorcher.  Only 2006/07 is close and there are only five years within even 0.5ºF, which is a big number when talking about average climate over an entire hemisphere. 

Source: NCDC
In the contiguous US, we were a country divided.  The entire Pacific coast and much of the southwest saw their warmest Dec-Feb on record.  Most of the remaining mountain west was much above average.  Most of the east was below average, but no climate zones has a top-10 coldest winter.  

Source: NCDC
However, February was a fairly exceptional month in the east with many climate zones in the upper midwest and the north east observing their coldest or 2nd coldest February on record.  

Source: NCDC
Adding to the intensity of the winter in the east, especially during February was an active storm track, with winter storms affecting the southeast and record snowfall observed along the Massachusetts and Maine coasts.  Boston and Worcester set all time records for snowiest February and winter.  Frequent storms and persistent cold led to a remarkable snowpack.  In Eastport Maine, snow depths increased from 0 on the 24th of January to 78.5 inches on the 16th of February.  If only Utah enjoyed such a storm cycle this year!
Data Source: NOAA/NOHRSC
Global temperature analyse show what a remarkable February that it was in the eastern US and eastern North America as a whole, which was by far the coldest region on the planet relative to climatological averages.  In contrast, western North America and a vast swath of Asia and Africa were well above average.  The Heat Miser is winning, but Snow Miser can still have his fun from time to time.  

For Utahn's, the main question now is can we set the all-time low snow record at Alta?  I'm now giving that a 60% chance.  The countdown is on!

Wednesday, March 18, 2015

I Give Up!

According to the Utah Avalanche Center, Alta Guard has had only 213.5 inches of snow since November.  Yesterday I waited for the bus at 6:45 am in a pair of shorts.  We set record highs the past 3 days at the Salt Lake City airport.  Even with a bit of cooling today, we're still well above average.

The models show dry, mild conditions continuing over northern Utah through the weekend.  There are hints that we might see a trough passage next week, but this looks to be another example of a trough "slipping through the net," followed by the return of the ridge that has been seemingly omnipresent over the west all winter.

I've decided that I am going to root for Alta Guard to break its all time record for least snowy season (314.5" for November through April).  Yeah, I've talked about the possibility of breaking this record a few times, but now I am going to root for it, going against everything that I stand for as a human being.  If we are going to suffer like this, we may as well get something to show for it.

Monday, March 16, 2015

Cage Match II: Tug Hill Plateau vs. Wasatch Mountains

Last year, after I spent some time enjoying the intense snowstorms of the Tug Hill Plateau, we did a fun comparison of the snowfall climate of that region with the Wasatch Mountains (see Cage Match: Tug Hill Plateau vs. Wasatch Mountains).  I thought we might have a look see at how things are faring this year.

Regular snowfall observations on the Tug Hill Plateau are available from a National Weather Service cooperative observer at a site known as "Hooker" (for reasons I've never understood) on the northern plateau near the village of Copenhagen.  So far this year, Copenhagen has had 259.4 inches of snow, although data for the last 3 days are missing, and they may have added a bit to the total the past couple of days.  

Source: NOAA Regional Climate Centers
A web cam image from my friends at shows a healthy snowpack in nearby Montague.  

Now let's return to Utah.  The cooperative observer at Alta, UT, has reported only 217.8 inches of snow this year (note the scale change), far less than Hooker, although there are some days with missing data.

According to the Utah Avalanche Center, Alta Guard has had 213.5 inches, so something in the lower 200s is pretty reasonable.  The ski area, which I believe measures higher on the mountain, reports 254 inches.  Even if we go with that, my friends on the Tug can rub our noses in it as it appears they are running ahead of Alta.  Yeah, I know the terrain on the Tug is limited for skiing (there are some good turns to be had over 400 vertical feet at Snow Ridge), but this post is more about fun with snow than skiing.  

Update on the Italian Snowfall Record

I am still trying to find an official report regarding the world-record 24-hour snowfall claim in Capracotta, Italy.  Not surprisingly, Google searches turn up tons of news reports with regards to the record.  Everyone loves a good story.  Then I found this report in USA Today that states the following:
Despite gobs of initial media attention, that total may have been wildly inflated. Officially, the town picked up "only" about 3 feet of snow, which was then blown around by strong winds into massive snowdrifts, greatly exaggerating the totals.
Not surprisingly, that story has garnered far less attention.  In the end, I suspect this will go down as as a major snowstorm, but one that falls short of record status, as we discussed a few days ago.  Nevertheless, I look forward to more official analysis of the event just to be sure.      

Saturday, March 14, 2015

World's Snowiest Ski Area Is Closed

Mt. Baker, which averages nearly 650 inches of snow a year (thought to be the highest of any ski area in the in the world) and received a world record 1,140 inches of snow in the 1998/99 season, is temporarily closed for lack of snow.

A video discussing the decision is provided below.  

SNOTEL data shows a pretty grim picture with regards to snowpack in the Pacific states and southern Arizona and New Mexico.  

The causes of these low totals, however, vary geographically.  In southern Oregon, California, and southern Arizona and New Mexico, it's been a combination of below average precipitation and warmth has led to the low snowpack.  In contrast, in Washington, it's actually precipitation has actually been near or above average, but most storms have brought rain to elevations that typically receive snow. 

Let's have a look at data from a couple of SNOTEL stations in the North Cascades.  The first is Wells Creek, which is west of the Cascade crest and not far from Mt. Baker Ski Area.  It's eleveation, 4200 feet, is also close to that of the base of the ski area.  

The snowpack at Wells Creek currently contains less than 5 inches of snow water equivalent (i.e., the depth of water you would have if the snowpack melted).  For this location, that is the lowest on record (red line is the minimum, but data goes back only to 1996).  Average at this location is for mid March is something closer to 30 inches.      

Source: Pacific Northwest River Forecast Center
The plot below shows a different perspective for the same site.  The black line shows the accumulated precipitation since 1 October, the grey line the average accumulated precipitation, the red line the median snowpack snow water equivalent, and the blue line the observed snow water equivalent.  Note that precipitation for the season is actually a bit above average.  The snowpack is low primarily because a greater-than-average fraction of precipitation this winter fell as rain instead of snow.  There are a couple of periods during which the snowpack declines, indicating that some melting contributed too, but it was the warmth of the storms that has largely been the problem. 
Source: NRCS
One sees a different picture, however, if you go to high elevation, especially east of the Cascade Crest which has a somewhat colder wintertime climate.  At Harts Pass, which is at 6500 ft, the snowpack is very close to average.  

Depending on how the next few weeks play out, this could be a fairly interesting spring in the Cascades.  Given the lack of snow in the low-to-mid elevations, access to some remote areas via logging roads might come much earlier than usual, while a decent snowpack lingers in the upper elevations.  This might be advantageous for some early spring touring in the North Cascades and on volcanoes like Mt. Adams, that typically are hard to access until very late in the spring.  

Friday, March 13, 2015

The Spring Break Forecast

There's nothing quite like the beaches of the Great Salt Lake during spring break (ha ha)!  Photo: Emerald View Resorts.
Spring break is upon us and college students will be flocking to the shores of the Great Salt Lake for some hard-core partying.  

Ooops, this is Utah.  Spring break is about recreating, meaning skiing, climbing, mountain biking, hiking, etc.  Looks like you will be able to do any of these this week.

The flow over the area is expected to be characterized by ridging or split flow through the end of next week.  Below is the medium range guidance for Wednesday afternoon.

Source NWS
Such a pattern means above average temperatures will likely prevail for the period.  This weekend will be especially warm and looks marvelous statewide, with temperatures well above average (We may crack 70 on at the Salt Lake airport on Sunday).  Sunblock!

Overall, precipitation should be below normal through the period, but there are a few wrinkles to consider.  Although this weekend looks nice, the stormtrack, while weak, is just to our north and northwest and does flirt with the norther portion of the state early next week.  Right now, it looks like we'll stay warm and dry through Tuesday except for perhaps a few showers near the Utah–Idaho border.  

Although we're in split flow, there are a couple of weak troughs that may bring a threat of showers to the state midweek.  Below is the forecast from the GFS for Wednesday afternoon showing the moisture and shower activity.  We'll have to see how this comes together, but keep an eye on the forecasts and adjust your adventuring accordingly.  Right now, I doubt there will be a major dumpage for skiers.  At least there will be corn to harvest the next few days.   

Beyond that, the forecasts currently call for mild temperatures and drier weather later next week, with a possible trough approaching during the weekend.  That's so far out that I suggest you check the forecast midweek and adjust your plans accordingly.  By and large, however, it looks like there will be plenty of opportunity to do just about anything, other than deep powder skiing, during the spring break period.  

Thursday, March 12, 2015

A Chance to Listen to an Icon

Dr. Lonnie Thompson receiving the Medal of Science from President George W. Bush
I have lots of ideas for blog topics today, but I'm tabling them as I would like to alert everyone to an opportunity to hear from a pioneering research scientist.

At 6 PM on Thursday March 26th, Dr. Lonnie Thompson, Distinguished University Professor, School of Earth Sciences at The Ohio State University and Senior Research Scientist, Byrd Polar Research Center, will give a University of Utah Frontiers of Science lecture entitled "Global Climate Change, ENSO, and Black Swans: A Paleoclimate Perspective from the World's Highest Mountains" in 220 Aline Skaggs Wilmot Building (ASB).  More detailed information available here.

This will certainly be a great talk for Wasatch Weather Weenies, lovers of mountains, and those passionate snow and ice.  Lonnie's research involves ice-core paleoclimate studies from tropical and subtropical glaciers and ice fields in the Andes, Himalaya, and Mt. Kilimanjaro to high-latitude ice caps in Greenland and Antarctica.  He has documented the climate history of these regions and the remarkable change that has occurred in recent decades.  More details can be found at his Ice Core Paleoclimatology Research Group Web Page.

Huascaran, Peru Expedition, 1993.  Photo Lonnie Thompson.
 Arrive early.  This is likely to be a well attended talk.

Wednesday, March 11, 2015

Is This a World Record Snowfall?

Capracotta, Italy.  Source:
Yesterday evening, reports of a world-record 100.8 inch snowfall in 18 hours in Capracotta, Italy went viral.  The original source of this report is the Italian weather site (click here to access).  94.5 inches was reported in Pescocostanzo.  This sort of thing is what the Wasatch Weather Weenies live for!  Let's have a look.

Capracotta is located in central Italy on the east side of the Apennine Mountains at an elevation of 1,421 meters (4,662 ft).  The Adriatic Sea lies to the east.  The Tyrrhenian Sea is to the west.

The storm occurred on the 5th of March when an intense cyclone developed over the region.  The storm was deepest over the Tyrrhenian Sea, but a secondary low center also developed over the Adriatic Sea (plots below based on 6-hour GFS forecast, red square indicates approximate location of Capracotta).

GFS SLP forecast valid 1200 UTC 5 March 2015
The overall pattern favored the transport and concentration of high integrated water vapor values (contours below, warmer indicating higher values) over the southern Adriatic Sea, which then wrapped cyclonically around the mesolow into the Apennines and to Capracotta.  Wind vectors below are for 850 mb, very near the altitude of Capracotta.

GFS integrated water vapor and 850-mb wind forecast valid 1200 UTC 5 March 2015
I couldn't access Italian radar for the event, so I'm going with the GFS 6-h precipitation forecast for mid-day just to show how this leads to heavy orographic precipitation over the eastern Apennines (Magenta is more than 1 inch of water equivalent in 6 hours - keep in mind that the GFS does not fully resolve the Apennines).  The sea level pressure analysis further above also shows a pronounced mesoscale pressure ridge upstream of the terrain, consistent with terrain blocked flow and typically accompanied by an pocket of colder air.

Thus, it is clear that a major snowstorm rocked the Capracotta area.

Now we get to the more difficult issue concerning snowfall amounts.  It is not uncommon for remarkable snow totals to be reported in the media after big events.  I did a quick Google search and was able to find another claim of a world-record 24-hour and storm-total snowfall in the Pyrenees just a few weeks ago.   Unfortunately, I haven't been able to find any discussion of who took the measurements in Capracotta or Pescocostanzo, or how those measurements were taken.  The current world record is 76 inches in 24 hours set at Silver Lake, Colorado, and we've discussed some of the issues even with this record previously (see Looking Back at the World 24-Hour Snowfall Record).

Although I believe the snowfall in Capracotta was exceptional, there are a few reasons why I'm a bit skeptical of the 100 inch report.  First, it is so far above anything that has been previously reported that I'm inclined to doubt it until I see some sort of analysis of how and where the measurements were taken (previous claims on the world record, such as a 77 inch total over the Tug Hill Plateau, have not survived such scrutiny, although they have almost always been exceptional events).

Second, my experience with extreme snowfalls is that they tend to be low-density events (i.e., the water content of the snow is low) and thus typically feature lots of dendritic crystals with little riming.  These crystals form at temperatures between -12 and -18 ºC.  The event in Capracotta was relatively warm (sea-level temperatures were 6ºC and forecast 850 mb temperatures were 0 to -5ºC, so this dendritic growth region would have been elevated.  Those crystals would have had to survive without being beaten to hell by atmospheric turbulence (tough given the strong flow) and also avoid riming in the warm environment.  However, it's possible that the damming of cold air along the Appennines helped in this regard.

Third, and consistent with the item above, this looks to have been a fairly high density snowfall.  The photos at show what looks to be high density snow.  It's balled up and supporting people who are walking on it.

Although I'm skeptical, I remain open minded about this event.  Surprises happen in meteorology, and I look forward to seeing a careful analysis of this event.  I guess the old Ronald Reagan line, trust but verify applies here.  One thing is for sure - they got pounded with a hell of a lot of snow and it appears that even if 100 doesn't hold up, they may likely have a big number in the end.  Jealous!

If you see any official reports or analyses, please post a comment below with a link.

Addendum @ 3:25 PM:

More discussion of this at the Capital Weather Gang.  They actually suggest that the world record is 90.6 inches on Mt. Ibuki, Japan in February 1927, which I was completely unaware of.  I sometimes wonder if we should just have a "do over" for all these snowfall records!