Forecast for the Uintas Area Mountains

Mark Staples
Issued by Mark Staples on
Friday morning, February 19, 2021
STRONG WINDS TODAY will transport snow and keep the avalanche danger HIGH in all northerly facing terrain above treeline as well as east and southeast facing terrain. Human triggered avalanches are VERY LIKELY. Avalanches will be at 2-5 feet deep and hundreds of feet wide.

All other terrain near and below treeline has a CONSIDERABLE avalanche danger. These areas require careful snowpack evaluations, conservative decision-making, and cautious route-finding.

Riding conditions are excellent. Take advantage of the many areas of gentle, rolling terrain that isn't steep enough to produce avalanches, but make sure to avoid being under slopes steeper than 30 degrees.
Low
Moderate
Considerable
High
Extreme
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Weather and Snow
Nowcast-
The most notable thing about the weather this morning is that winds have increased from the southwest and are averaging 20-30 mph with gusts up to 35 mph. No snow has fallen as of 5 a.m., and temperatures are mostly in the low teens F and a bit colder at upper elevations.
Forecast-
Today will be snowy and cloudy but only an inch or two of snow should accumulate. Winds should blow from the west and maybe increase a bit more blowing 30 mph gusting to 40-50 mph at upper elevations. I'm unsure if these winds will only blow above treeline at the highest elevations or if they will reach very far below treeline. Temperatures today should mostly in the teens F and not warm up much.
Futurecast-
A better chance for more snow comes tonight through Sunday morning when 5-8 inches of snow should fall.
Snowfall totals since last Friday are generally 20-24 inches of snow (2-2.4 inches of water). Total snow depths range from 3.5 to 6 feet. Scroll to the bottom of the page to see two graphs showing snowfall since last Friday.

Looking for real-time temps, snow, or wind?
Click here and then on the "western Uinta" tab for western Uinta specific, weather station network.
Recent Avalanches
Yesterday near Gold Hill, Ted spotted a few avalanches that were several days old. Along the Mirror Lake Highway, I spotted two large slides (one & two).
Ted added these words of wisdom: "To me, these are tricky conditions, there were some natural avalanches, some slopes have filled back in, and things look and feel good to go. Normally this time of year we are starting to venture out more on bigger slopes, but the current snowpack is still not to be trusted even though conditions feel great under our sleds and skis."
What really shows the type of avalanches to expect in the Uintas now is the slide in the photo below from Wednesday. It was a very large explosive triggered avalanche in upper Weber Canyon that was 4.5 feet deep and 400 feet wide that failed on a persistent weak layer of faceted snow. Notice how it also broke mid-slope. Craig describes this slide in this video.
Other smaller slopes below this avalanche released which is a major red flag regarding the extent of the weak layers under these avalanches and the connectivity of the slabs involved.

More obs, trip reports, and avalanches found here.
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Avalanche Problem #1
Persistent Weak Layer
Type
Location
Likelihood
Size
Description
The most dangerous and likely problem is large slab avalanches breaking on persistent weak layers near the ground. These slides will be 3-5 feet deep and hundreds of feet wide. Today these avalanches are very likely on slopes loaded by strong southwest and west winds.
These persistent weak layers exist on all west, north, east, and southeast facing terrain. Yesterday I triggered collapses and cracks shooting 100 feet in front of me as I rode near the top of a 29 degree, southeast facing slope (photo and video below). If it had been just a few degrees steeper, it would have produced an avalanche.
Here's the tricky part about this avalanche problem - Places with a thick, hard slab on top of this weak layer will be a little harder to trigger and it may be the 1st or 2nd or even 10th person on a slope who triggers it. The main point is that tracks on a slope DO NOT mean it is stable.
Avalanche Problem #2
Wind Drifted Snow
Type
Location
Likelihood
Size
Description
Strong winds are the main weather factor that cause avalanches in the Uintas. They form cohesive slabs of wind drifted snow which can quickly overload persistent weak layers near the ground. Winds can load a slope 10x faster than snow falling from the sky.
A good example is the avalanche in the photo below on a south facing slope on Bald Mtn loaded by northwest winds. Today's southwest and west winds have plenty of fresh powder to transport onto leeward slopes.
There was lots of evidence of recent northwest winds yesterday, but these winds had not reached far into the trees. Notice the wind drifting on Bald Mountain in the photo, but the trees in the foreground were untouched by winds and still snow-covered. Today's winds may reach further below treeline.
Additional Information
Total snow depth graph from the Camp Steiner weather station for Friday, Feb 12 to Thursday, Feb 18.
Total snow depth and snow water equivalent from the Trial Lake SNOTEL site for Friday, Feb 12 to Thursday, Feb 18.
We will update this forecast by 7:00 AM tomorrow, Saturday, February 20th.
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General Announcements
If you see or trigger an avalanche or just wanna let me know what you're seeing 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.