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Forecast for the Logan Area Mountains

Toby Weed
Issued by Toby Weed on
Sunday morning, December 27, 2020
There is CONSIDERABLE danger on steep drifted slopes at upper and mid elevations facing the northern half of the compass. People could trigger dangerous avalanches failing on a sugary persistent weak layer. 1 to 2 feet deep slab avalanches are likely and could be triggered remotely or from a distance. Avalanches are possible at all elevations, but you can find safer conditions in lower angled terrain out from under steep slopes, and in sheltered areas. Shallow snow coverage dictates careful travel, and hitting rocks and other obstacles still presents a serious risk in the backcountry.
  • Cracking and collapsing indicate unstable snow.
  • Continue to avoid and stay out from under drifted slopes steeper than about 30 degrees.
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Learn how to read the forecast here
Special Announcements
Thanks to the generous support of our local resorts, Ski Utah, and Backcountry, discount lift tickets are now available. Support the UAC while you ski at the resorts this season. Tickets are available here.
Weather and Snow
Several inches of new snow accumulated yesterday and overnight in the mountains, and we expect nice shallow powder conditions. Lower angled slopes will once again offer the best riding and skiing conditions, because on steeper slopes you will still sink into the underlying less consistent older snow. Overall snow coverage is still very shallow in the Logan Zone, and the snow that was on the ground in November and early December is very loose and sugary. In many places you still sink all the way to the ground when you hop off your sled.
Observers continue to report triggering booming audible collapses in many areas. These whumpfing sounds are a red flag indicating unstable snow, telling us that dangerous avalanche conditions exist.
Expect snow showers to diminish this morning and clouds to gradually clear in the mountains today. High temperatures will be in the lower twenties at 8500', with a light breeze from the west. Tomorrow, a winter storm is expected to impact areas to our south, with significant snow possible... Up north it will likely just be cloudy and windy with some snow showers, but not much in the way of accumulation. There is potential to ring in the New Year with a more significant winter storm.
Recent Avalanches
Last weekend there were many natural and several human triggered avalanches in the backcountry.
This one on White Pine Knowb in upper Bunch Grass was remote triggered by backcountry skiers.
From a distance Wednesday, an observer noticed a recent large natural avalanche in the Mount Naomi Wilderness, in Upper Cottonwood Canyon.
The broad slab avalanche below a cliff band involved wind drifted snow and failed on a sugary persistent weak layer.
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Avalanche Problem #1
Persistent Weak Layer
Type
Location
Likelihood
Size
Description
Many slopes in the region are plagued by layers of weak faceted snow formed during the prolonged November dry spell. Avalanches failing on a persistent weak layer can be very sensitive, and they might be triggered remotely, from a distance, or worse from below!
The faceted crystals at the bottom of the snow pack are getting bigger and are becoming more well developed. This is becoming depth hoar, and it will likely haunt us in the future!
Avalanche Problem #2
Wind Drifted Snow
Type
Location
Likelihood
Size
Description
Drifting of fresh snow from westerly winds yesterday and overnight built sensitive softer slabs and may hide older drifts from view. During the week winds drifted snow into lee slope starting zones and around terrain features like gullies, cliff bands, and sub ridges. Stiffer drifts or older wind slabs are usually not as sensitive as soft new ones, and they may allow people to get out on them and into avalanche paths before releasing. People are likely to trigger soft or harder slab avalanches of wind drifted snow, 1 to 3 feet deep, on some steep upper elevation slopes, especially where drifts formed on weak, sugary, or faceted snow.
  • Even a small avalanche could be very dangerous due to shallow early season snow conditions.
This small natural avalanche of wind drifted snow in Hell's Kitchen failed on a sugary persistent weak layer.
Additional Information
Everybody should make time to examine and practice with your avalanche rescue equipment, and convince your backcountry partners to practice with you. Watch our companion rescue video HERE
My tip for avoiding avalanches in the backcountry is to keep your slope angles low. Avoid and stay out from under slopes steeper than about 30 degrees. Get a tool to measure slope angle and practice with it in the backcountry. Watch the video HERE.
Paige shows what we are talking about when we mention faceted snow in our forecasts. Watch the video HERE
General Announcements
Visit this website with information about Responsible Winter Recreation by the Utah Office of Outdoor Recreation.
We've kicked off Season 4 of the UAC podcast with a Conversation with American Avalanche Institute owner Sarah Carpenter. You can stream it HERE or wherever you get your favorite podcasts.
The Tony Grove Road is not maintained for wheeled vehicles in the winter.
EMAIL ADVISORY. If you would like to get the daily advisory by email you subscribe HERE.
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.
I will update this forecast by around 7:30 tomorrow morning.
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.
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