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Forecast for the Logan Area Mountains

Toby Weed
Issued by Toby Weed on
Monday morning, January 4, 2021
Dangerous avalanche conditions and CONSIDERABLE danger exist at mid and upper elevations in the backcountry. People are likely to trigger dangerous 1 to 2-foot-deep slab avalanches failing on a sugary persistent weak layer. Avalanches are possible at all elevations, but most likely at upper and mid elevations on drifted slopes facing northwest through southeast. Avalanches could be triggered remotely or from a distance.
A winter storm with heavy snow and drifting tonight will cause rising avalanche danger in the backcountry, and natural avalanche activity is quite possible.
  • Cracking and collapsing indicate unstable snow.
  • Avoid and stay out from under all drifted slopes steeper than about 30 degrees.
Low
Moderate
Considerable
High
Extreme
Learn how to read the forecast here
Avalanche Watch
AVALANCHE WATCH FOR NORTHERN BEAR RIVER RANGE IN EFFECT FROM 10 AM MST THIS MORNING TO 6 AM MST TUESDAY, 01/05/2021.
THE AVALANCHE DANGER FOR THE WARNING AREA COULD RISE TO HIGH TONIGHT.
HEAVY SNOW COMBINED WITH DRIFTING FROM STRONG WINDS WILL CREATE WIDESPREAD AREAS OF UNSTABLE SNOW. BOTH HUMAN TRIGGERED AND NATURAL AVALANCHES MAY BECOME LIKELY. STAY OFF OF AND OUT FROM UNDER SLOPES STEEPER THAN 30 DEGREES.
Special Announcements
We are offering a Backcountry 101 Avalanche education class in Logan on Jan 21 and 22. . Details and registration here.
Check out our new and relevant Blog featuring Paige and Greg discussing Danger Ratings and Persistent Weak Layers....HERE
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
It looks like about 5 inches of medium density snow fell at upper elevations yesterday. There is 33" of total snow at the 8400' Tony Grove Snotel, containing only 73% of normal Snow Water Equivalent.
Yesterday's fresh snow is capping a variety of older snow surfaces including glittering feathers of surface hoar, small-grained sugary snow, and thin radiation crusts. Westerly winds drifted the fresh snow at all elevations, creating shallow wind slabs and causing better cohesion in existing soft slabs that sit on widespread weak sugary or faceted snow. 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 or come out of your skis. Dangerous avalanche conditions exist on steep slopes at mid and upper elevations, and people are likely to trigger avalanches involving old snow.
The National Weather Service in Pocatello has issued a Winter Storm Warning for the northern Bear River Range, from this early afternoon through tomorrow morning. A winter storm will impact the Logan Zone, beginning this afternoon, with up to about a foot of accumulation expected at upper elevations and intensifying southwest and westerly winds. It will be mostly cloudy today, with snow and blowing snow in the afternoon, and 8500' high temperatures are expected to be near 35°F. Looks like a break in the weather, a brief period of high pressure Wednesday, and then another modest storm, with more snow possible Thursday.
Our tests show that people could trigger dangerous avalanches.
Recent Avalanches
On Saturday, a snowboard rider triggered a small avalanche across Beaver Creek Canyon from the backside parking spot. The small slab avalanche was on a very steep drifted lower elevation slope, and indicates potential for a widespread problem with buried persistent weak layers as the season progresses..
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Avalanche Problem #1
Persistent Weak Layer
Type
Location
Likelihood
Size
Description
The buried persistent weak layer problem involving sugary faceted snow is a very dangerous and notoriously tricky avalanche problem, and it is responsible for most fatalities, injuries, and close calls in the Logan Zone.
Yesterday, I triggered subtle collapses and extensive cracking, and several 1'-deep frowns, 20 to 30' wide and 10 to 20' above me on a 25 degree slope on the backside of Beaver Mt., on an east facing mid-elevation slope. A developing and now more cohesive soft slab was failing on loose sugary faceted snow above a stout crust that was on the snow surface in November.
Cracking like this is a red flag inticating unstable snow.
  • Avalanches failing on a persistent weak layer can be very sensitive, and they might be triggered remotely, from a distance, or worse from below!
Avalanche Problem #2
Wind Drifted Snow
Type
Location
Likelihood
Size
Description
Fresh drifts formed on weak layers that have developed on the snow surface or preserved under about an inch of new snow. Soft drifts of new snow, up to about a foot deep, could be quite sensitive, and a smaller avalanche overrunning a slope with poor snow structure could create a much larger avalanche. Old, harder wind slabs are fairly widespread at upper elevations near ridge tops and in and around terrain features like gullies, cliff bands, and sub ridges. People could trigger 1 to 3-foot-thick slab avalanches of wind drifted snow on steep slopes, especially where drifts formed on weak, sugary, or faceted snow.
  • Avalanches of wind drifted snow could be triggered remotely or from a distance.
  • Harder wind slabs may allow people to get out on them before releasing.
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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