Forecast for the Logan Area Mountains
Issued by Toby Weed on
Friday morning, January 31, 2020
Friday morning, January 31, 2020
The snow is stable and the danger LOW on most slopes in the Logan Zone, but heightened avalanche conditions exist, and there is MODERATE danger on drifted upper elevation slopes. People could trigger avalanches of wind drifted snow in exposed terrain. Dangerous avalanches failing on a persistent weak layer are unlikely yet still a possibility on isolated slopes with shallow snow and poor snow structure.
- Evaluate snow and terrain carefully.
Low
Moderate
Considerable
High
Extreme
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Weather and Snow
It's 18°F at the 8400' Tony Grove Snotel this morning, and there is about 2 inches of new snow from yesterday's little storm, with 0.2" of Snow Water Equivalent. There is 79 inches of total snow, containing 122% of normal SWE. West winds picked up significantly early this morning and are currently blowing around 30 mph, with gusts in the 50s at the CSI Logan Peak weather station. And, it's 15°F at 9700'.
Several inches of fresh snow fell at upper elevations this week, and shallow powder conditions are really nice, especially in sheltered terrain. Drifting from west winds has created heightened avalanche conditions in exposed upper elevation terrain. We observed a thin rime-crust and heavily rimed trees above about 8000' in open terrain on windward slopes in upper Providence canyon yesterday.
We'll see partly sunny skies today and 8500' high temperatures are expected to be around 32°F, with 16 mph west-northwest winds. Increasing clouds tonight, with mostly cloudy skies, low temperatures around 17°F, and 13 to 16 mph west-northwest winds. It will be sunny tomorrow, with a high temperature near 42°F, and 13 to 16 mph southwest wind. A powerful Pacific storm is expected to arrive late Sunday, with 8 to 14 inches of new snow possible at upper elevations by Monday.
Recent Avalanches
We found easily triggered and manageable soft wind slabs and cornice falls this week on drifted upper elevation slopes. West winds increased significantly early this morning and today's drifts will be stiffer, deeper, and perhaps a bit less manageable.
Yesterday, we noticed a recent avalanche of wind drifted snow, triggered by a sizable cornice fall off Red Pine Ridge that ran at least 500 vrt' into Richard's Hollow.
Avalanche Problem #1
Wind Drifted Snow
Type
Location
Likelihood
Size
Description
Several inches new snow fell this week on upper elevation slopes, and northwesterly winds were plenty strong enough to move it around. This weeks drifts were sensitive to human triggering, but they will likely be stiffer and more stubborn today. Harder wind slabs sometimes allow people to get out on them before releasing.
- Watch for and avoid stiffer drifted snow near ridge lines and in and around terrain features like cliff bands, scoops, gully walls, and sub-ridges.
- Avoid ridge top cornices, which can break much further back than expected and start avalanches on slopes below.
Avalanche Problem #2
Persistent Weak Layer
Type
Location
Likelihood
Size
Description
Although increasingly unlikely, dangerous human triggered avalanches failing on a deeply buried persistent weak layer remain possible on isolated upper elevation slopes. Some avalanches might step down into buried persistent weak layers, involve large volumes of snow, and be quite dangerous and destructive. Tuesday, we found very poor snow structure on slopes with shallow snow on the west side of the south ridge of Beaver Mountain. Our stability tests showed potential for avalanches failing on sugary faceted snow buried by the New Years storm.
It's easy to find very weak, sugary or faceted snow where the snow is shallow. This example is from the south Ridge of Beaver Mt. (1-28-2020)
Additional Information
We triggered several shallow avalanches of wind drifted snow and cornice falls in the backcountry on the south ridge of Beaver Mt. earlier in the week.
We noticed a few large fresh roof avalanches off metal barn roofs in the Bear Lake Area on Friday. Many are still holding lots of heavy snow, and gradual melting is causing them to drip and creep. Keep and eye on the kids, animals, and vehicles because more significant roof avalanche activity is likely, especially when both day and night temperatures are above freezing.
General Announcements
Are you looking to improve your avalanche skills? We are offering a Backcountry 101: Introduction to Avalanches class at Powder Mountain February 14-15. Info and sign up HERE
The anual CROWBAR backcountry ski race will be on Saturday, February 8. The unique and classic backcountry race will be held at the Swan Flat/Garden City Trailhead in upper Logan Canyon. There are four divisions (Junior, Recreation, Heavy Metal & Race) with different climbs, descents, and technical booters. Participants must carry avalanche rescue gear (beacon, shovel, probe) and can use alpine touring gear, telemark skis, or splitboards. Register on UltraSignup, or sign up to volunteer at this year's race!
Thanks to the generous support of our Utah ski resorts and Ski Utah, we have discount lift tickets available. All proceeds from these go towards paying for avalanche forecasting and education! Get your tickets HERE.
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Remember your information can save lives. If you see anything we should know about, please help us out by submitting snow and avalanche observations....HERE. You can also call us at 801-524-5304, email by clicking HERE, or include #utavy in your tweet or Instagram.
This forecast is from the USDA Forest Service, which is solely responsible for its content. The forecast describes general avalanche conditions and local variations always occur.
I will update this forecast before about 7:30 tomorrow morning.