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Forecast for the Salt Lake Area Mountains

Trent Meisenheimer
Issued by Trent Meisenheimer on
Tuesday morning, December 28, 2021
The avalanche danger is HIGH on mid and upper elevation aspects facing west through north and east, where strong winds and recent snowfall have created dangerous avalanche conditions. Both natural and human-triggered avalanches are likely. Traveling in or below avalanche terrain is not recommended.
There is a CONSIDERABLE avalanche danger on mid and upper elevation aspects facing southwest, south and southeast. Low elevations have a MODERATE avalanche danger.
Low
Moderate
Considerable
High
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Avalanche Warning
THE AVALANCHE DANGER IS HIGH WITH DANGEROUS AVALANCHE CONDITIONS.
AN AVALANCHE WARNING HAS BEEN ISSUED FOR THE MOUNTAINS OF MUCH OF THE STATE OF UTAH, INCLUDING THE WASATCH RANGE...BEAR RIVER RANGE...UINTA MOUNTAINS...AND THE MANTI-SKYLINE.
HEAVY DENSE SNOWFALL AND STRONG WINDS HAVE CREATED DANGEROUS AVALANCHE CONDITIONS. BOTH HUMAN TRIGGERED AND NATURAL AVALANCHES ARE LIKELY. STAY OFF OF AND OUT FROM UNDER SLOPES STEEPER THAN 30 DEGREES.
Weather and Snow
Under cloudy skies, the overnight temperatures have plummeted, and it's cold with current mountain temperatures in the single digits °F. Winds are blowing from the west-southwest at speeds of 10-20 mph across the upper elevation ridgelines. My hope is they are finally trending down in speeds. It's been a long six days of strong winds. The last snowflakes are currently being squeezed from the atmosphere leaving us with 6-10 inches of new snow containing 0.47-0.58 inches of water in the past 24 hrs.
Many people have asked me what happened to our epic storm? Where is all the snow? Well, Jim Steenburgh covered this question in his blog HERE. This morning, I decided to add up the water amounts for the past five days. Talking to the Alta Avalanche Office, they manually measured at Alta Collins 9,600', 4.14 inches of water for the past five days. In the Uintas, the Trial Lake weather station reads 5.4 inches of water. If you take the normal Utah snow ratio of 12:1, it snowed 50 inches at Alta and 65 inches at Trail Lake. Other parts of the state also ended up with inches of water and feet of snow. Despite the annoying south winds, the water and snow totals are impressive.
AND we still have more snow on the way, with yet another storm starting Wednesday evening lasting into Friday with another 10-20 inches of new snow possible.
Recent Avalanches
In the backcountry, two avalanches caught my attention. The first is Scotties Bowl in upper Little Cottonwood, Scotties is a north-facing slope at 9,800' in elevation, and the avalanche was 100 feet wide and 4 feet deep. The second avalanche was in Alexander Basin and was remotely triggered from 250 feet away. The avalanche was roughly 2 feet deep, 80 feet wide, and ran 1,500 feet to the valley bottom (pic below).
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Avalanche Problem #1
Persistent Weak Layer
Type
Location
Likelihood
Size
Description
Heavy snowfall and strong winds continue to overload a buried persistent weak layer of faceted snow down near the ground. This layer exists on mid and upper elevation aspects facing west through north and east. Avalanches failing on this weak layer may be triggered remotely (from a distance) or below. Any avalanche failing on this layer may break down 2-6' deep (possibly deeper), propagate hundreds of feet wide, and run downhill thousands of feet.
Traveling on or below slopes approaching 30 degrees or steeper is NOT recommended.
Look at the picture below if you're confused by how serious this problem is (triggered Sunday with explosives). Now imagine all that snow instantly moving 30-60 mph downhill with you completely submerged and out of control. You go to take a breath; all you manage to do is inhale the snow, clogging your mouth; you can't breathe. You'll be lucky to be alive when the avalanche comes to a stop (all it takes is one tree, then it's lights out). Sure rescue gear might save you, but it might not. This avalanche problem is the real deal and should be avoided with large safety margins. Avoidance is the key.
Avalanche Problem #2
Wind Drifted Snow
Type
Location
Likelihood
Size
Description
Strong winds have created both hard and soft slabs of windblown on all aspects at the mid and upper elevations. Although the winds have been mainly from the west/southwest, winds this strong can channel snow around terrain features and create fresh drifts on all aspects, including well-down off of ridge lines. You may even find fresh wind drifts at unusually low elevations below 8,000'.
Additional Information
Craig Gordon, Mark Staples, Trent Meisenheimer, Toby Weed, and Brett Kobernik discuss the current avalanche situation. They discuss some things we know and some things we don't know.
General Announcements
Who's up for some free avalanche training? Get a refresher, become better prepared for an upcoming avalanche class, or just boost your skills. Go to https://learn.kbyg.org/ and scroll down to Step 2 for a series of interactive online avalanche courses produced by the UAC.
This information does not apply to developed ski areas or highways where avalanche control is normally done. 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.