Wasatch Weather Weenies

Yesterday (Saturday) was the opening day for ski season for me with a warm up lap up Collins Gulch at Alta to shake off the rust and see what needs to be fixed or replaced.   There were a few people that had the same idea as me.   And plenty of entertainment to be had.  Look carefully and you can see the 22-degree halo.   One change on the Mt. Baldy skyline is the addition of Wyssen Tower Avalanche Control Systems.   I find their presence on Mt. Baldy unsightly, but understand why Alta is moving to them as they attempt to reduce and sunset the use of the 105 mm Howitzer, which has enormous risks.   If you haven't seen these towers in action, here's a video. I'm not sure if these are UDOT's, Alta's, or some combination of both, but the deployment boxes for the Wyssen Towers and O'bellx pods were sitting in the Wildcat lot just ready to be loaded and then flown in by helicopter.   A lot happens so you can go skiing on a powd...

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, ...

If you are out and about in the backcountry this weekend, you may encounter surface hoar , beautiful but weak ice crystals that form on the snow surface when it cools below the frost point.  We saw plenty of it yesterday at lower elevations during our ski tour.   Surface hoar is sometimes described as recrystallized powder, but as I understand it, that's incorrect.  Surface hoar is created through the growth of new crystals.  The formation process is similar to frost.  The snow surface cools below the frost point and ice crystals grow from the deposition of atmospheric water vapor onto the snow surface.  This process becomes highly effective under clear skies, when the snow surface can become quite cold, and when there is a strong temperature inversion.  It is also very effective near open water where there is a source of water vapor.   In contrast, recrystallized powder, or  near-surface facets,   form through the metamorphism...

Sorry to be Donnie Downer here but regardless of how much snow there might be in the Salt Lake Valley right now, the mountain snowpack situation in northern Utah remains well below median except on north aspects in Little Cottonwood Canyon and the south side of the high Uintas.  The latest numbers from NRCS SNOTEL stations show we are at 69% of median in the Jordan/Provo/Utah Lake basin, 69% of median in the Weber River Basin, and 68% of median in the Lower Bear.   Northern Utah stations at or above median include Mining Fork in the Stansbury Mountains, Snowbird, and several sites on the south side of the High Uintas.   Focusing on the Jordan/Provo/Utah Lake basin, the reality is that the water equivalent of snowfall so far this year has been sufficient to put us at median.  The problem is that some of that snow fell in October and early November and didn't survive.  One can see this in the time series below, which shows several early season storms fol...

The Pacific Storm Track is angry my friends and about to unleash some serious weather on the western United States.   I'll focus on one component of the forecast, precipitation, and will use the downscaled NAEFS-derived forecast below to summarize. Over the next 7 days, the average amount of precipitation (liquid equivalent) produced by the 52 NAEFS members in the mountains of northern California exceeds 10 inches in portions of the Coastal Mountains and Cascades/far northern Sierra.  At these "favored" locations the driest members produce over 5 inches and the wettest over 20 inches.   The plume for the Mt. Shasta Ski Bowl at 8,000 ft elevation shows a mean of almost 8" with most of the NAEFS members clustered between 6 and 8.5", although the full range of all members is about 3.5 to 12".  Our snowfall algorithm is known to overestimate snow-to-liquid ratio in this part of the world so be cautious interpreting the snowfall plume.  Snow levels will be ...

Questions about possible linkages to climate change are bound to arise whenever something unusual or exceptional happens, and this year's weak snowpack and high number of avalanche fatalities is no exception.   Let's start with what we know and what we can say with some confidence.  We are in a period of climate warming, driven by human activity, and this is changing the snow climates of the western United States.  Weather and climate variability give us ups-and-downs even in a changing climate, but we are seeing a shift to warmer mean temperatures, more winter warm spells, and fewer winter cold spells.   Trends in snowfall and snowpack measures vary, however, depending on the measure, regional climate, and elevation.  In northern Utah, at elevations below about 6500 feet, we are seeing declines in the fraction of wintertime precipitation that falls as snow, more frequent mid-season snow-loss events, and a decrease in the amount of wintertime precipita...

As I write this, dawn is breaking on the final day of January, which promises to be the nicest weather day of the winter so far with our deepest snowpack, fresh snow (although probably tracked out in resort terrain that was open yesterday), and bluebird skies. Sadly, it sounds like there was another fatality yesterday in the backcountry adjacent to the 9990 chair at Park City Mountain Resort.  We have talked previously about the high frequency of fatalities there and some of the heuristic traps that contribute to them (see The Lure of Dutch Draw ).  Today has all the hallmarks of the type of day that causes skiers to push it into steeper terrain with fresh snow, beautiful weather, and a season of pent-up powder frustration.  Don't let Powder Fever cloud your judgement.   We have another shot at a major winter storm Tuesday night and Wednesday associated with an upper-level trough passage within large-scale northwesterly flow.  Below is the GFS forecast vali...

I was deeply saddened to learn of the death yesterday of a 31-year-old snowboarder in Dutch Draw, a backcountry area along the Park City Ridgeline and often accessed from the 9990 chairlift at Park City Mountain Resorts.  My deepest condolences to family and friends.  This one hit me in the gut harder than most, I think in part because there have been so many deaths in Dutch Draw over the years.  The Utah Avalanche Center has an extensive record of avalanche fatalities in Utah (available here ) and it appears this is the 4th since 2005.  The accident reports suggest that in all cases, the victims entered the backcountry after riding the 9990 chairlift.    Although knowledge of terrain, weather, and snowpack is important for evaluating avalanche risk, our judgement and ability to perceive risk is often clouded by other factors.  Avalanche accidents happen when the perception of risk does not match the reality.  Ian McCammon has investigated the rol...

Yesterday afternoon, I learned via social media feeds and news reports of a possible early Christmas morning avalanche at Belleayre Mountain Ski Center in the Catskill Mountains of New York (see Avalanche damages lodge at Belleayre Mountain Ski Center from CBS6 News in Albany).   Photos provided to CBS6 by Belleayre Mountain Ski Center show the damaged Overlook Lodge filled and surrounded by debris. Source: Belleayre Mountain Ski Center via CBS6 News Source: Belleayre Mountain Ski Center via CBS6 News The ski center also reported that they were closed and that "supersaturated snow from the Yahoo trail let loose and slid into the Overlook lodge." Source: Belleayre Mountain Ski Center Belleayre is located in the Catskills of southern New York.  Those from the New York City area would describe it as "upstate," but it was definitely "downstate" for someone like me who grew up northwest of Albany.   The ski center has a vertical drop of 1,404 feet and a top el...

An article last week in The Telegraph explored some of the confusion that exists about "itinerary" ski runs in Europe and highlights many of the ambiguities and contrasts that exist concerning controlled vs. non-controlled terrain at ski resorts in Europe.   Source:  https://www.telegraph.co.uk/travel/ski/articles/what-is-an-off-piste-itinerary-ski-run/ Until I saw the article, I'd never heard the term "itinerary" ski run before, which highlights some of the cultural challenges that exist when skiing in a new region where approaches to resort avalanche hazard may vary.  Essentially, itinerary runs are typically ungroomed routes.  For example, freeride-verbier.com  states that itinerary ski runs in the Swiss Alps are designated off-piste routes and marked on the ski map, but they are not maintained or controlled (see link ).  They are indicated with yellow lines on a piste map. The culture and approach to avalanche "control" (I put that in h...

Snow accumulations in the Wasatch Mountains are probably starting to give snow-safety professionals heartburn, especially considering the forecast. Automated snow depth measurements at Alta Collins show 8 inches on the ground as of 6 AM MDT this morning.  At the Daybreak measurement site at 9250 feet above Canyons Village at PCMR, its up to 10 inches.  It's tough to say how much to trust these early automated snow depth sensors, and they may or not be representative, but given the persistent easterlies over the past couple of days, I would not be surprised if the upper-elevations of the Park City Ridgeline had a snow depth similar to that at comparable elevations in upper Little Cottonwood.  Certainly the camera at Crescent Ridge is looking snowy this morning. Source: Park City Mountain Resort, downloaded 8:07 AM MDT Higher up, at the top of Collins, Alta is looking wintery. Will we get more? Sure.  Perhaps a few more snow showers today in the central...

Humans have a difficult time grasping events that our outside their range of experience.  I learned a lesson in that yesterday.  Interested in exercise and seeing the aftermath of the remarkably warm storm on Saturday, my partner and I opted for a short, low-angle ski tour above Alta.  What we found was a remarkably stout and slick rain crust between above about 9200 feet to where we opted to quit climbing at 9500 feet. This is the type of rain crust that I recall from my youth in upstate New York.  Essentially impenetrable by skis.  In this case, it was about 1 cm thick, with the snow below that still setting up. Meanwhile, it was graupeling and at the time it was 0 to 8 cm deep, with the variability due to wind transport on the very slick surface. We opted to head back down, skiing a low angle line.  Certainly what I thought was a very low angle line.  However, as my partner descended, the graupel began to sluff.  I shouted to him ...

Weatherwise, things are pretty ho-hum right now, so it's worth a look at the Kesspler Peak Avalanche that was triggered around noon yesterday.  Below is the video report from Trent Meisenheimer and Mark Staples of the Utah Avalanche Center.  A written accident report is available here . Pretty sobering stuff and a strong reminder that there still are scary monsters living in the basement, as Bruce Tremper likes to say.  It is very fortunate that nobody was killed or injured on the Cardiff Fork summer road/trail, which is used frequently for exits from up-and-over tours or to access upper Cardiff Fork from Big Cottonwood.  

It's very early in the ski season, yet a backcountry skier died in an avalanche on Imp Peak in the Madison Range of Montana on Saturday. Source: Friends of the Gallatin National Forest Avalanche Center Some basic information is available in this article from the Bozeman Daily Chronicle . This is a sad reminder that early snow is not necessarily safe snow.  The central Wasatch has had early season fatalities in the past, including within resort terrain, which is de facto backcountry during the preseason.  Keep this in mind when we start to see snow piling up again.  

As we discussed a few weeks ago, the ski season is never over until it's over .  That being said, we are probably very close to the "beginning of the end." By beginning of the end, I mean the onset of the rapid decline in snowpack on upper-elevation northerly aspects. The low-elevation snowpack already suffered a premature death in March with the beginning of the end produced by the unseasonably furnace-like temperatures we experienced in the middle of the month. The snowpack at mid-elevation and relatively sun exposed upper-elevation areas has, however, been able to stave off the beginning of the end for a remarkably long period of time.  For example, peak SWE at the Mill-D North SNOTEL was reached in early March.  Since then, there have been two melt periods, each followed by an accumulation period.  The most recent peak in SWE, achieved on May 1, was just a bit below the early March peak. At Snowbird, which benefits from both elevation and north aspect,...

I am once again out of town and once again the Steenburgh Effect is in full force. Yes, you can say that it snowed plenty while I was back in Salt Lake through yesterday morning, but the water equivalent rates have gone through the roof since I left.  Note the steeper slope of the current storm after I departed compared to the prior one when I was in town. Source: MesoWest Coincidence?  I think not. Of course that is entirely unscientific. It is mere coincidence I'm out of town, but sometimes I wonder... The snow overnight is also of high density, resulting in upside down snow.  That, and the addition of wind and further weight on weak layers that developed before the prior storm, is pushing the snowpack to the breaking point. The Utah Avalanche Center has issued a backcountry avalanche warning for the mountains of northern Utah, including the Wasatch. And, as I write this, Little Cottonwood Canyon is closed at Alta is interlodged.  Expected highwa...

A beautiful fall sunrise over Salt Lake City Salt Lakers were treated to a beautiful fall sunrise and crystal clear skies.  Days like this you just have to take a deep breath and suck it all in.   A quick look at the mountains reveals a new white frosting.  Data from Alta-Collins is AWOL this morning, but the NWS reports about 5 inches fell yesterday in the Town of Alta.  I'm not sure it looks like that much in weather cams, but I did notice that Alta is making snow or at least testing their snow gun near the Albion base.  Get up there now for first scratches.   Source: Alta.com Overnight forecasts for the rest of the week are a bit disappointing if you want more snow, but encouraging if you are in the snow-safety industry.  The latest NAM, for example, keeps us cool, but even with the next trough pushing through, brings us just some scattered snow showers and little in the way of well-organized precipitation.   Now that fall...