Forecast for the Moab Area Mountains

Eric Trenbeath
Issued by Eric Trenbeath on
Saturday morning, February 13, 2021
Heads up! Rising avalanche danger through the weekend! The avalanche danger is MODERATE this morning but will likely rise to CONSIDERABLE later today. New and wind drifted snow will add stress to buried persistent weak layers and deep and dangerous, human triggered avalanches will become increasingly more likely on steep slopes facing NW-N-SE. If we see more than about 6" of new snow, storm snow avalanches will be possible on all aspects. Backcountry travelers need to be alert to changing conditions such as accumulating and wind drifted snow. Look for signs of instability such as cracking and collapsing, and continue to avoid steep slopes facing NW-N-SE.
Low
Moderate
Considerable
High
Extreme
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Special Announcements
The accident report for the tragic avalanche that killed four skiers in Millcreek Canyon on Saturday, Feb 6, is complete. All were well-known members of the backcountry community and all of us at the UAC are deeply affected. Our deep and sincere condolences go out to the family and friends so affected by this accident.
The Geyser Pass Road is plowed. Conditions are snow-packed and icy and all-wheel drive is recommended. Expect snow to accumulate this weekend with no plowing until Mon or Tues.
The Lower Utah Nordic Alliance (LUNA) last groomed all trails with classic track on Wednesday. A few inches of new snow currently cover the track with more on the way.
Weather and Snow
24 Hour Snow 2" 72 Hour Snow 2" Base Depth in Gold Basin 38" Wind SW 5-10 Temp 22 F
Yesterday's storm turned out to be pretty much a bust. The next, stronger looking system is currently over western Utah with the trough projected to deepen over the region later today. A lot of factors point to a decent shot of snow out of this, but the splitty nature of the trough still gives me some cause for concern. Today, look for snow showers to develop around noon with 3"-5" possible by this evening. SW winds will be on the increase averaging 15-25 mph along ridge tops with gusts as high as 30. Snowfall should continue overnight with up to a foot possible by tomorrow. Snowfall should largely be over by Sunday morning along with an influx of cold air and a shift to northwesterly winds. The next system will move in Monday night into Tuesday.
Wind, temperature, humidity on Pre Laurel Peak (11,700')
Snotel site near Geyser Pass Trailhead (9600')
Storm totals at the Gold Basin study plot (10,000')
Snowpack Discussion
New snow and wind over the next 24 hours will cause an increase in avalanche danger as renewed stress is applied to existing slabs overriding buried persistent weak layers of loose, sugary, faceted snow. Slopes facing NW-N-SE will experience the most rapid rise in danger, and deep and dangerous human triggered avalanches will become increasingly more likely in these areas. Once we get more than about 6", avalanches involving new snow will be possible on steep slopes on all aspects. Backcountry travelers will need to be alert to changing conditions such as accumulating and wind drifted snow. Look for signs of instability such as cracking and collapsing, and continue to avoid steep slopes facing NW-N-SE.
Recent Avalanches
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Avalanche Problem #1
Persistent Weak Layer
Type
Location
Likelihood
Size
Description
Persistent weak layers of loose, sugary, faceted snow are present on many aspects and elevations. On slopes facing NW-N-E-SE, slabs 1'-3' deep exist on top of these weak layers. New and wind drifted snow will further stress these weak layers and deep and dangerous, human-triggered avalanches will become increasingly more likely. The danger increases with elevation, particularly on slopes with recent deposits of wind drifted snow.
The photos below illustrate classically poor snowpack structure with a clearly defined fist to 4 finger hard slab on top of weak, sugary, facets. In other words - strong snow over weak snow. Stability tests indicate a stubbornness to release but this only makes them harder to predict. It's like provoking someone with a violent temper - you don't know when they are going to explode. As long as this snow structure remains in place, I won't be provoking any steep northerly facing slope.
Avalanche Problem #2
Wind Drifted Snow
Type
Location
Likelihood
Size
Description
As winds ramp up later today be nn the lookout for the development of fresh drifts to to form on the leeward sides of ridge crests and terrain features, primarily on slopes facing NW-N-SE. Fresh wind slabs are often recognizable by their smooth, rounded appearance and cracking is a sign of instability. Areas with recent deposits of wind drifted snow will create additional stress on buried persistent weak layers increasing the likelihood of triggering a deeper and more dangerous avalanche.
Additional Information
For you snow geeks out there check out this snowpit from Chris Benson. This is how the pros record data. Compare the photo with the graph to see how it corresponds to the snowpack. The Y-axis is the snow depth. The X-axis represents the hardness of each layer. Remember we are looking for harder layers over weak layers. In this case, you can see how the area between 20-40 cms is problematic. The layer at 30 cms represents a thin crust with weak snow above and below. Above 40 cms there is a slab on top of the weak snow.
General Announcements
This forecast is from the U.S. Forest Service, which is solely responsible for its content. This forecast describes general avalanche conditions and local variations always occur.