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Forecast for the Logan Area Mountains

Mark Staples
Issued by Mark Staples on
Saturday morning, December 25, 2021
CONDITIONS ARE VERY DANGEROUS. Today both natural and human-triggered avalanches are very likely at mid and upper elevations facing East, West, and North where the avalanche danger is HIGH. All other slopes at mid and upper elevations have a CONSIDERABLE danger. At low elevations, avalanches will be possible and the danger is MODERATE.
Heads up - Because the new snow is generally dense and supportable, it won't seem like as much has fallen. The key point is that A LOT weight (over 3 inches of water) has been added to the snowpack which is adding a lot of stress to buried weak layers. Give yourself a wide safety margin today and avoid avalanche terrain.
Low
Moderate
Considerable
High
Extreme
Learn how to read the forecast here
Avalanche Warning
THE AVALANCHE DANGER IS HIGH WITH DANGEROUS AVALANCHE CONDITIONS. FROM 6 AM MST THIS MORNING TO 6 AM MST SUNDAY.
FOR THE MOUNTAINS OF MUCH OF THE STATE OF UTAH, INCLUDING THE WASATCH RANGE...BEAR RIVER RANGE...UINTA MOUNTAINS...AND THE MANTI-SKYLINE.
RECENT HEAVY SNOW COMBINED WITH STRONG WINDS WILL CREATE WIDESPREAD AREAS OF UNSTABLE SNOW. BOTH HUMAN TRIGGERED AND NATURAL AVALANCHES ARE LIKELY. STAY OFF OF AND OUT FROM UNDER SLOPES STEEPER THAN 30 DEGREES.
Special Announcements
Avalanche conditions are very dangerous across most of the State of Utah as discussed by our staff in the video below -
Weather and Snow
Since yesterday another 8-12 inches of heavy, dense snow (containing 0.9-1.4 inches of water) has fallen in the mountains. The two-day total for Tony Grove is snow containing 3.2 inches of water which is an incredible load....in other words the snowpack has increased by 33% in the last two days. The snowpack doesn't care how much snow fell, it only cares how much weight has been added to it, and this amount is a huge increase.
Winds this morning are blowing 25 mph gusting to 42 mph from the west on Logan Peak. Temperatures at many places are in the upper teens F which is about ten degrees cooler than yesterday.
Today skies will be mostly cloudy in the morning with maybe some light snowfall that will taper off this afternoon. Winds will continue from the west at 20-40 mph, and temperatures may only warm by a few degrees. Tonight and tomorrow morning, snowfall should pick up again with another 6-8 inches falling by tomorrow afternoon. Expect very strong winds from the southwest tomorrow.
The skiing and riding have improved dramatically. Even though it doesn't look like it from the valley where rain has been falling, the mountains have 3-4 feet of supportable snow on the ground now.
Recent Avalanches
There were no avalanches reported yesterday, but that doesn't mean there weren't any because clouds and snowfall made it hard to see many slide paths. A group of riders I spoke with at the Birch Creek TH near Preston reported experiencing many collapses which is the EXACT same thing as seeing an avalanche except the slope wasn't steep enough to slide.
A group in Gibson Basin experienced shooting cracks, another clear sign of unstable conditions.
Check HERE for all the latest observations and avalanche activity.
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Avalanche Problem #1
Persistent Weak Layer
Type
Location
Likelihood
Size
Description
Slab avalanches breaking on a persistent weak layer near the ground are likely today. This layer of weak, sugary facets can be found just above a hard ice crust that caps old snow from October and early November.
Yesterday in Paris Flats and Bloomington Canyon, my partners and I found this layer in every pit we dug (see the photo below) on slopes that faced the northern half of the compass. Avalanches breaking on this layer will be 2-4 feet deep or even more on heavily wind loaded slopes. Avalanches on this layer may also break hundreds of feet across.
Avalanche Problem #2
Wind Drifted Snow
Type
Location
Likelihood
Size
Description
Winds blowing from the south, southwest, and west have been transporting snow during the last several days. These winds drifted snow mostly on slopes that have a persistent weak layer of sugary facets near the ground. The problem with these wind slabs is that they will make avalanches breaking on the facets larger, deeper, and more deadly. Avoid any steep slope, and especially avoid any slope with obvious wind drifting where avalanches are very likely to occur.
Avalanche Problem #3
New Snow
Type
Location
Likelihood
Size
Description
On slopes that don't have wind drifted snow and don't have old facets near the ground, the new snow alone may produce soft slab avalanches. Subtle variations in the new snow like density changes can create a temporary weak layer. Yesterday we found a slight hardness variation in the new snow that caused it to break about 8 inches deep in our stability tests.
Additional Information
  • Always follow safe backcountry travel protocols. Go one person at a time in avalanche terrain, while the rest of your party watches from a safe area.
  • Check your avalanche rescue equipment, change your batteries, and practice often with your backcountry partners.
  • Be very careful, keep your speed down, and stay in control. Encounters with shallowly buried rocks or down trees in the early season have led to many season-ending injuries.
  • The gate at the bottom of the Tony Grove Road was closed yesterday to preserve snow on the road for grooming.
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.
  • Check out all the upcoming education classes and clinics HERE.
  • Please submit your observations from the backcountry HERE.
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