Wasatch Weather Weenies

Weather conditions are almost prime for being able to harvest corn and powder if you can work the north and south aspects.  Almost.  On upper-elevation north aspects, the snow on north aspects is surviving it's just not very deep and there's wind damage aplenty. Nevertheless, you can find creamy settled powder in some areas that skis surprisingly well.  Effort and perseverance can pay off. Meanwhile, hop across the ridge to the south side and you can find corn.  The south face of Mt. Superior got a lot of attention today.  We elected for other options, finding buttery conditions on our return to Alta.  Arguably, it needs a couple more cycles to truly corn up, but the skiing was just fine.  Really, if the wind hadn't done damage and if we had a bit more snow in the last storm, today would have yielded pretty good conditions for a corn and powder harvest.  Although the bounty wasn't great today, the skiing was better than expected...

Snowfall observations have been collected at Alta Guard for November through April since the 1945/46 season.  As noted in today's Utah Avalanche Center advisory, Alta Guard has measured 245" of snow since November, with 24.65" of water.  It does not appear that they will add to this total through the end of the month, which will result in the November to March snowfall being the second lowest on record, behind only 2014/15, when only 220.5 inches was recorded.  Although I still consider 1976/77 to be the worst snow year on record for skiers, mainly because the early season snowfall was so poor (even worse than this year, see Deep Dive: How Unusual Is Our Snowfall and Snowpack This Season , posted 9 Feb 2018), that season is now ahead of this one from a November to March snowfall perspective, with 283.5 inches.  Nevertheless, this has been a remarkably dismal snow season and one of only 6 seasons with less than 300 inches of snow at Alta Guard from November to Ma...

Sadly, the latest forecasts show scant precipitation over the next seven days.  There are a few ensemble members going for a small snowfall event early next week, but it's a low probability possibility.  With April upon us, I feel like instead of fall, winter, and spring, this year we had two falls and then moved right into spring.  Snow was sparse through the middle of February.  Things picked up for about a month, and now we are limping along once again.  The Alta Snowfall History shows a cumulative seasonal snowfall of only 321 inches with 8 deep-powder days (based on a minimum of 10 inches or more of snow).  The latter is about half of average.  Five of those deep powder days occurred from Feb 15 to March 17, which now stands as the closest thing to a month of winter that we saw this year.  It's possible that we have more dumps in the future.  April can do sometimes bring the goods.  Nevertheless, even if it comes around, ...

Some remarkable photos and videos of extreme dust storms in the Mediterranean Basin and the mountains of Eurasia have gone viral on Twitter.  To begin, here's how things looked on March 22nd on Crete and March 23rd in Santorini, Greece. Thick Saharan dust in Heraklion, Crete yesterday, March 22! Report: remi.k1/ https://t.co/0yRQD8IWuL pic.twitter.com/LUvXxm0Zpz — severe-weather.EU (@severeweatherEU) March 23, 2018 Spectacular Saharan dust scene from Santorini, Greece on Mar 23rd. Report: George Loftsalis pic.twitter.com/Mp32C2fH9g — severe-weather.EU (@severeweatherEU) March 25, 2018 In addition to bad air quality, such storms lead to dust deposition in the mountains of Eurasia, leading to "snirty" snow (a take on part snow part dirt).  The photos below are from the Caucasus Mountains near Sochi, Russia. Sochi (Russia) ski slopes covered in orangish Saharan dust over the past several days. Image: margarita_alshina IG pic.twitter.com/hX3JBEnHxB — seve...

Snow observations are very difficult to make well and even when they are done following "protocol" they still have uncertainties and ambiguities. Let's take the latest storm as an example.  The ground prior to the storm was quite warm, and this leads to variations in accumulation depending on the characteristics of the surface.  Let's suppose, for example, that you decided to head out and measure the accumulation on the grass this morning.  Here's what you would have found this morning.  First, the grass on most lawns is beginning to grow and is of variable height.  This in turn affects the transfer of heat from the relatively warm ground to the snow, leading to small mounds and variations in snow height and depth.  I was able to measure anything from 2 to 4.5 inches of snow on the lawn depending on where I placed the ruler (apologies for not having my metric ruler handy!).  This is one of the reasons why it is recommended that snowfall m...

Mid February marked a turning point for the upper-elevation snowpack in the central Wasatch, which now sits at 70% or more of median for this date at all four SNOTEL sites (Snowbird, Brighton, Mill D North, Thaynes Canyon).  Source: NWS At Mill-D North and Snowbird, you can see the gap close between the median trace (purple line) and this season's trace (green line) from about mid February to the present.  Source: NWS Source: NWS These sites are relatively high, however, so they tell an incomplete picture of the snowpack.  At lower and mid elevations, the situation isn't nearly as rosy.  Sadly, those elevations are poorly sampled with regular observations and it is difficult to quantify how far behind they are.  In addition, the central Wasatch are doing much better than the northern or southern Wasatch.   Some of the more depressing SNOTEL observations are provided by Ben Lomond Peak to the north and Timpanogos Divide to the south, wh...

After returning from Seattle, I was finally able to sample the atmospheric river aftermath in the Wasatch backcountry today.  A polite descriptor of the conditions would be "variable."  It seemed strange, even in the upper elevations that were above the snow level, how little snow the storm produced given the amount of water it generated.  Maybe it blew to Evanston.  Graupel was found in many areas.  In a few pockets it had collected into piles perhaps 20 cm deep.  I don't know why, but I always enjoy digging into piles of graupel. Exiting, we got a view down Little Cottonwood with lower clouds beginning to develop over the Salt Lake Valley.  Periods of snow look likely for the mountains through Sunday night, although it's not looking like a major event.  The NAM is spitting out a total of about 4", although the always optimistic GFS and NAM-3km are putting out higher totals.  Anything appreciated at this point.

By now, you've probably heard that an atmospheric river is coming to Utah tonight and tomorrow. Atmospheric rivers are corridors of strong atmospheric water vapor transport.  Such transport is dependent on both the water vapor content of the atmosphere and the strength of the flow.  Values are typically highest when the water vapor content of the atmosphere is high and the flow is strong.  Atmospheric rivers can be associated with heavy precipitation, but strong atmospheric water vapor transport, by itself, doesn't generate precipitation.  Some forcing is needed to lift the airmass, form clouds, and generate precipitation. In the case of an atmospheric river, one possibility is to have it cross a mountain barrier, which yields strong upslope flow and precipitation enhancement.  This happens commonly in the mountains of California during atmospheric river landfall. Another option is to have large-scale forcing, such as the ascent typically found near cold...

Atmospheric rivers are narrow corridors of strong atmospheric moisture transport, often connected in some way to moisture exported into the midlatitudes from the tropics or the subtropics.  Although Utah sometimes sees the remnants of weakened atmospheric rivers, bonafide atmospheric river conditions in Utah happen only a few times each cool season. However, we have a shot at one making it to the state Wednesday night and Thursday if model forecasts hold.  The average integrated water vapor transport in forecasts produced by the Global Ensemble Forecast System for 0600 UTC 22 March (0000 MDT Thursday) shows strong values extending from the Pacific Ocean northeastward into Utah.  Values exceeding 250 kg/m/s (outlined by red line) indicate atmospheric river conditions, and most of Utah is covered. Source: NWS Two ingredients favor atmospheric river penetration into Utah in these forecasts.  The first is that the atmospheric river is strong on the coast, with in...

I've been surveying the forecasts for spring break and it is looking like a week where you can do just about anything if you are adaptive and pay attention to forecasts. I think everyone is well aware that the weekend is for skiing in the Wasatch where the snow continues to pile up.  Alta-Collins got 10 inches overnight and has another 4" through 2 PM.  Between the cloud cover and the low temperatures, the snow should be holding up well on higher elevation north aspects.  Over three inches of water has fallen in the last three days, making this one of the more productive storm cycles of the period.  My advice is that you ski until you drop through the weekend. Monday is a tougher call and one that you will need to make for yourself.  Good skiing may persist, or you might opt to head south for adventures in southern Utah.  It will be a cool day, but sunny statewide.  Tuesday looks spectacular, with upper-level ridging over the state.  Wedn...

"The best deep-powder skiing is not found in the lightest snow but rather in snow with enough 'body' to provide good flotation for the running ski." - Ed LaChapelle, 1962 You can have your bottomless blower pow.  You can rave about pit deep 4%.  You can have it all.  The truth is, those deep, dry days don't provide the best powder skiing.  Give me some Cascade concrete and and put some cold smoke on top of it.   And that's what we found on sheltered upper-elevation north aspects today.  What we didn't find were people. We pulled into the White Pine lot at 8:15 and found only two cars in the lot.  Two!  While gearing up, I kept waiting for the yellow lights to start blinking and then the sound of incoming shells as there's no way that there can only be two cars in the lot on a powder day.   Yet the dream was true.   Then the day dawned clear, with a postcard view down Little Cottonwood on the climb up...

Storms have produced some impressive precipitation amounts (water equivalent) for March from yesterday afternoon through this morning.  Some totals through 7-8 AM or so this morning include .78" at the Salt Lake City Airport, just over an inch in Olympus Cove, 1.25" at Spruces, and 1.54" at Alta Collins.   Sadly, much of that water fell as liquid in the lower to middle elevations.  For example, 0.68 of the 1.54" that fell at Alta Collins fell at temperatures at or above 32ºF.  During that period, snow levels were initially at almost 9000 feet and lowered to about 8000 feet.  They have since dropped to the valley floor and as of about 8 AM, it is snowing at the University of Utah. At Alta Collins, the automated interval snow-depth sensor suggests about 10 inches of snowfall.  Initially, that snow was probably a mixture of graupel and white sludge, but densities dropped with snow levels overnight, so what is there should be right-side-up....

It's worth a look at the combined cloud/radar and NAM cloud/precipitation forecast loop below to get an idea of the lack of organization of precipitation systems forecast to impact the weather of northern Utah over the next 2-3 days.  Note their banded or "blobular" structures.  Blobular is of course a highly scientific word (ha ha) used here to describe cellular features produced by a model that due to it's sparse grid spacing (12-km) is incapable of producing convective storms that look like those of the real world.  The chaotic nature of those precipitation features means if you are looking for a precise forecast of when and how much it is going to rain or snow over the next couple of days, you've come to the wrong place.  Let's start with perhaps the easy part: Today.  A combination of instability, strong flow, and vertical wind shear means we will see some showers and thunderstorms this afternoon.  The NAM forecast sounding for 2200 UTC (4 PM MD...

All generalizations are wrong, and that is especially true if one is talking about weather, snow, and snowpack.  A quick look at the numbers from this past season reveals some surprises and multifaceted reasons for the low snowpack that exists across our region. Let us begin at the Salt Lake International Airport where there are relatively long weather records.  Total precipitation (liquid equivalent) since 1 November is 3.00 inches, well below the 1981–2010 average for the period of 5.81 inches.  However, during that period, the airport actually received 39.9 inches of snow, which is not far behind the 1981-2010 average of 45.6 inches.   Snowfall at one location, by itself, tells a pretty incomplete story. It tells an incomplete story because the period from 1 November to 12 March is also the warmest on record, with a mean temperature of 39.9˚F.  Only three previous periods come close: 1933/34 (39.6˚F), 1977/78 (39.5˚F), and 2014/15 (39.4ºF). Sourc...

Don't be fooled by the balmy weather, the loss of valley snow, and the diminishing snowpack in the mountain valleys.  It is only March 12th.  There will be more powder skiing and perhaps even some tastes of winter in the valley.  Spring in the Intermountain West is typically a rollercoaster ride.  Indeed, we're in for sum ups and downs this week.  Monday and Tuesday look mild, with the NWS forecast below showing highs Monday and Tuesday of 64˚F and 74˚F at the Salt Lake Airport.  The weather then "gets interesting" on Wednesday in advance of a cold front that is currently forecast by the NAM to be over eastern Nevada by 3 PM MDT (2100 UTC) 14 March.  Thus, Wedensday right now looks breezy to windy with perhaps some showers around.  We may get a frontal passage Wednesday night if things hold together as presently advertised by the models. What happens later in the week depends strongly on the structure and depth of the upper-level troug...

Today is a sad day as both Mountain Dell and North Fork Park have closed for nordic skiing, presumably for the season. I'd like to give a shout out today to everyone at The Utah Nordic Alliance (TUNA) and Ogden Nordic for their efforts this season.  Despite sparse snow and remarkable warmth, both tracks were open quite a bit thanks to a great deal of shoveling and careful grooming.  Mountain Dell North Fork Park I grew up cross country skiing, but only this year did I start skate skiing, and it totally changed my perspective on the sport and gave me a whole new challenge in skiing.  Talk about suffering!  However, over the past couple of months, form and fitness have led to remarkable improvement.  I may be slow, but I'm not as slow as I was in December! I also discovered that when the powder skiing is terrible, the skate skiing is often great.  Thus, skating helped me survive a less than desirable snow season.  I'm still hoping to ge...

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.  

Innsbruck.  Host city of the 1964 and 1976 Winter Olympic Games. The Wasatch Weather Weenies blog will be taking a road trip next winter and spring as I have received a Fulbright Award and will be serving as a Visiting Professor of Natural Sciences at the University of Innsbruck.  What an opportunity.  Innsbruck sits in the heart of the Tyrol within where the Wipptal (Wipp Valley) meets the Inn Valley.   Looking southward at Innsbruck and the Wipptal under "Foehn" conditions (warm southerly flow).  The Brenner Pass to Italy is shrouded in cloud. The University of Innsbruck has one of the strongest atmospheric sciences programs in Europe and its Institute of Atmospheric and Cryospheric Sciences is known worldwide.  When I think of Universities with a ideal settings for mountain meteorology and snow science, the University of Innsbruck immediately comes to mind.  I will be developing and teaching a four-credit graduate level class...

Good for me, bad for you, the Steenburgh Effect is back.  Sponsors: Please send me a new hat! Although temperatures will only be in the 40s in the valley, I think today is the type of day that should cause an outbreak of Spring Fever.  We've had a warm winter, but no matter what you do in January, the days are short and the sun angle low.  We're now into March and the days are noticeably longer and the sun is beginning to feel like a microwave.  Today dawns with clear skies and will be full of bright sun.  Spring fever is here.  Ski conditions in the Wasatch on Sunday and Monday were outstanding.  My hand has healed up enough that I was finally able to get out and do some touring.  Note the froth at the mouth in the photo above (really just sunblock, but who knows, maybe I was drooling).  It was good to sample some of the Greatest Snow on Earth finally.  Unfortunately for you, that means the Steenburgh Effect is back.  Best ...

I know what you're thinking.  This was the storm that wasn't.  But don't let down your guard or give up hope.   Despite our skunking yesterday and last night, snow is still coming. The analysis loop below shows what happened.  The surface-based front made it to Salt Lake City yesterday around 3 PM and the accompanying surface trough has lingered just to our south.  The precipitation, however, was less cooperative, providing a bit of snow for the northern Wasatch (1-3" according to the Utah Avalanche Center), but never really making it down to the central Wasatch or the Salt Lake Valley for reasons discussed in yesterday's post.  Currently, the surface trough appears to be draped across the southern Salt Lake Valley, but is a bit amorphous.  Note the north winds near and around the airport and the south winds near and around Point of the Mountains.  The Salt Lake Valley will likely see a return of southerly flow today as the surfac...