HEADS UP -
Last night's shot of snow has our structurally challenged weak layers teetering on the edge.
Pockety and most pronounced near and above treeline, a CONSIDERABLE avalanche danger is found where additional snow stacks up on top of a pre-existing, weak layer of sugary snow. Human triggered slides breaking deeper and wider than you might expect are LIKELY, especially on steep, upper elevation slopes facing the north half of the compass.
Mid elevation terrain at treeline offers MODERATE avalanche danger and human triggered avalanches are POSSIBLE on steep, shady slopes.
Looking for LOW avalanche danger? Well then, you've got plenty of options. Simply swing over to the south half of the compass or tag some lower elevation trailhead shots where human triggered avalanches are UNLIKELY.
Storm snow stacks up on a variety of old snow surfaces and some are quite hard and slick. New snow avalanches on sustained steep slopes may run further and faster than you might expect. Something to consider if you're tagging a big, technical line.
The image above illustrates our setup... notice the smooth texture of the new snow on top of rough, granular looking weak snow underneath.
Now... here's what's going on. You remember the midwinter drought of January and February? You're thinking, hmmm... vaguely. Well, while we might forget what we had for lunch yesterday (tofu, spinach, kale salad :), the snowpack has an amazing memory and stores each weather event in its hard drive. And, those prolonged dry mid winter months created a persistent weak layer (PWL) of extremely fragile, sugary facets on the snow surface which were buried by very low density snow from two weeks ago. Despite nearly record breaking heat last week, the sugary layer remains cold, dry, and weak. This combo is found on mid and upper elevation slopes facing the north half of the compass along with a sliver of southeast facing terrain. This is our new problem child, especially where a cohesive slab rests on top. Mark commented... "To be honest, it's hard to believe how dry and weak this layer is until you see it and feel it with your own hands."
Here's where it gets tricky... large swaths of upper elevation terrain facing the north half of the compass were blasted by the winds prior to our recent storms and weak snow distribution is spotty at best. That means you'll need to evaluate each slope on an individual basis.
Ted was in the Gold Hill zone yesterday and reports... "I did have one good collapse with this piece of snow cracking out above me and it did not slide because of the low slope angle. There are a few places where the slab is connected just enough to overload the weak snow underneath." Ted know the Uinta's like no one else and has an excellent summary of his travels HERE.
In older news-
A falling piece of cornice on Tuesday in upper Moffit Basin triggered an avalanche (2' deep by 200' wide). This slide is a big red flag and a portent of things to come. I explain the set up in this video.
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NOWCAST-
And then... it snowed! A band of moisture intensified as it slid across the region late yesterday, delivering 6" of slightly denser than average snow with about .50" H20. Light snow showers and thick clouds drape our mountains this morning and southwest winds hardly spin mountaintop anemometers, blowing just 10-15 mph along the high ridges. Temperatures feel winter-like, registering in the teens and low 20's. A fresh coat of white paint delivers a two-fer and goes a long way to improve riding conditions along with a shot of increased endorphins to help stoke powder starved spirits :)
FORECAST-
Look for mostly cloudy skies with on again, off again snow showers throughout the day. 3"-5" of snow by days end seems reasonable. Winds are gonna be variable this morning, but turn westerly and increase late in the day, blowing to 30 mph near the high peaks. Temperatures don't vary much from where we're at this morning and then crater into the single digits overnight.
FUTURECAST-
A break in the action is slated for Monday and Tuesday with another potentially shot of snow developing midweek.
Trip reports and current state of the snowpack observations are found HERE.
Looking for real-time temps, snow, or wind?
Click HERE and then on the "western Uinta" tab for western Uinta specific, weather station network.
Your observations are important, so please let me know what you're seeing... click HERE and contribute to this amazing community based program
The information in this forecast expires 24 hours after the day and time posted, but will be updated by 07:00 Monday, March 7th.
Before it gets too crazy, now is the time to book an avalanche awareness presentation for your group, club, or posse. You can reach me directly at 801-231-2170 or [email protected]
This forecast is from the U.S.D.A. Forest Service, which is solely responsible for its content. This forecast describes general avalanche conditions and local variations always occur.
