Forecast for the Logan Area Mountains
Issued by Toby Weed on
Monday morning, January 13, 2020
Monday morning, January 13, 2020
CONSIDERABLE danger exists on upper and mid elevation slopes, and people are likely to trigger avalanches of wind drifted snow, perhaps failing on a buried persistent weak layer. Loose and soft slab avalanches of new snow are likely on many steep slopes and possible at all elevations. Heavy snow and intensifying southwest winds will cause rising avalanche danger during the day.
HIGH danger is likely to develop on some drifted upper elevation slopes, especially in the northern part of the Logan Zone. Very dangerous conditions will become more widespread late tonight and tomorrow, with large, fast moving, and long running natural avalanches possible.
- Stay off and out from under steep wind drifted slopes.
- Avoid travel in avalanche terrain and stay clear of avalanche run-out zones.
Low
Moderate
Considerable
High
Extreme
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Avalanche Watch
IN EFFECT FROM 6 AM MST THIS MORNING TO 6 AM MST TUESDAY
FOR THE BEAR RIVER RANGE IN SOUTHEAST IDAHO.
THE AVALANCHE DANGER FOR THE WATCH AREA WILL RISE TO HIGH TONIGHT, WITH VERY DANGEROUS AVALANCHE CONDITIONS LIKELY ON TUESDAY
HEAVY SNOW AND DRIFTING FROM STRONG WEST WINDS WILL CREATE WIDESPREAD AREAS OF UNSTABLE SNOW. BOTH HUMAN TRIGGERED AND NATURAL AVALANCHES ARE LIKELY. AVOID TRAVEL IN AVALANCHE TERRAIN. STAY OFF OF AND OUT FROM UNDER SLOPES STEEPER THAN 30 DEGREES.
Weather and Snow
It's 17°F at the 8400' Tony Grove Snotel this morning, and there is another 9 inches of new snow with .9" Snow Water Equivalent from yesterday and overnight. There is 84 inches of total snow, with 122% of average SWE for the date. The station reports 3.4" SWE since Wednesday (1-8-20) It's 9°F at the CSI weather station at 9700' on Logan Peak, and west winds are currently blowing about 25 mph, with a 50 mph gust earlier this morning
Drifting from increasing west winds today will cause the avalanche danger to rise and become more widespread. Dangerous avalanche conditions already exist on drifted upper and mid-elevation slopes. Heavy snowfall and strong southwest winds tonight and tomorrow will create HIGH avalanche danger, especially in the northern part of the Logan Zone, with fast moving and long running natural avalanches possible.
Expect snow showers to continue in the mountains today, with 3 to 7 inches of accumulation possible. 8500' high temperatures will be around 12°F, west winds 24 to 29 mph, and wind chill values will be around -9°F. Snowfall could be rather intense tonight, with 9 to 13 inches of accumulation possible. Low temperatures are expected to rise to around 21°F, with strong, 24 to 32 mph southwest winds, and wind chills around -8°F. Heavy snowfall will continue tomorrow, with 11 to 17 inches possible, and southwest winds 29 to 31 mph. Expect high pressure aloft developing for a short stay midweek. Another storm is expected to impact the area late Thursday into Friday.
Recent Avalanches
Friday, a rider triggered and rode out of an avalanche on a south facing slope @ 9000' in Boss Canyon, Franklin Basin near state line. The avalanche was about 15" deep x ~50' wide.
A rider triggered a 2' deep and 100' wide avalanche on an east facing slope at around 8200' in elevation near White Pine Creek on Tuesday, 1-7-2020. No one was caught or injured.
A close call occurred Saturday (1-4-2020) when a rider was caught, carried, and partially buried at about 9000' on an east facing slope above Hidden Lake in Gibson Basin, a couple miles north of the state line out of Beaver Creek Canyon. The avalanche of wind drifted snow was about 2' deep and around 150' wide.
Avalanche Problem #1
Wind Drifted Snow
Type
Location
Likelihood
Size
Description
People are likely to trigger 2 to 4 foot deep avalanches of wind drifted snow on upper and some mid elevation slopes. Avalanches are possible on many other mid elevation and some lower elevation slopes as well.
- 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.
- Wind slabs are often rounded and chalky looking, and they might sound hollow, like a drum.
- Soft fresh wind slabs can be quite sensitive, and are often remotely triggered. Hard wind slabs can be more devious, sometime allowing one to get out on them before releasing.
- 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
Human triggered avalanches failing on a buried persistent weak layer are likely on some upper and mid elevation slopes and possible at lower elevations. The cold weather Christmas week created sugary weak surface snow in many areas. Some avalanches might be triggered remotely, from a distance or below.
Friday's sled triggered avalanche in Boss Canyon was on a south facing slope at around 9000' in elevation, and we triggered a collapse on a south facing slope on White Pine Knob at about 8900'. Leading us to suspect particular instability on upper elevation south facing slopes.
Avalanche Problem #3
New Snow
Type
Location
Likelihood
Size
Description
Loose powder sluffs and shallow soft slabs of drifted new snow are possible on steep slopes at all elevations. Even small avalanches can be quite dangerous if you get dragged into trees or other terrain traps below.
Additional Information
Paige discusses our concerns about the drifted in east faces in upper Providence Canyon:
General Announcements
New UAC Podcast - An Avalanche Forecaster, a Meteorologist, and an Economist Walk Into a Bar..... 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.