Forecast for the Logan Area Mountains
Issued by Toby Weed on
Friday morning, January 17, 2020
Friday morning, January 17, 2020
Very strong south winds yesterday and overnight, and heavy snow this morning created HIGH danger on some upper elevation slopes. Dangerous avalanche conditions exist on many slopes in the backcountry, and human triggered avalanches of wind drifted snow are possible at all elevations. Natural avalanches are also possible today, and some could fail on a buried persistent weak layer and be large, destructive, and very dangerous. You can find safer conditions at lower elevations, on lower angled slopes, and in sheltered terrain.
- Evaluate snow and terrain carefully. Use caution while route finding, and make conservative decisions.
- Avoid travel on drifted slopes and continue to stay clear of avalanche run-out zones.
Low
Moderate
Considerable
High
Extreme
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Weather and Snow
Area Snotel sites aren't updating, but 5 inches of new snow has already fallen early this morning at Beaver Mountain. Temperatures are dropping and winds are diminishing a bit at the CSI weather station at 9700' on Logan Peak. It's 14°F, and last night's strong south winds have veered from the northwest, and are currently blowing around 25 mph, with a 71 mph gust around 0200.
Deep powder blankets the Bear River Range. The fresh snow is so deep and soft it is keeping riders off of steep upper elevation slopes. Riders are finding plenty of challenge though, and fantastic powder in lower angled and lower elevation terrain. Dangerous avalanche conditions exist on drifted upper and mid-elevation slopes, with human triggered avalanches likely, and large natural avalanches possible.
The upper restrooms in the Tony Grove Campground on 1-15-2020, buried by feet of fresh powder and 96 inches of total snow.
Expect strong winds and heavy snowfall in the mountains this morning as a sharp cold front passes through the area. Heavy snowfall this morning will become showery in the afternoon, and 5 to 9 inches is expected to fall on upper elevation slopes. 8500' high temperatures will fall to around 18°F, and 13 to 18 mph west winds will increase to 33 to 38 mph by afternoon, with gusts around 50 mph. It'll be mostly cloudy tonight, with low temperatures around 7°F, 8 to 10 mph west-southwest winds, and wind chills around -8°F. Benign weather is expected for the weekend as the pattern shifts, and a high pressure system builds over the area. It will be mostly sunny in the mountains tomorrow, with high temperatures around 28°F, and 6 to 9 mph west-southwest winds. Although there is still a fair amount of uncertainty, but the next storm looks like it'll arrive in the middle of next week.
Recent Avalanches
Tragically, a snowmobiler was killed in an avalanche Wednesday near Ketchum ID, in the Baker Creek drainage of the Smoky Mountains. Here is a link to the Sawtooth Avalanche Center's Forecast.
A large hard slab avalanche was observed Wednesday morning in the Rodeo Grounds on the east side of Logan Peak. It may have been remote triggered from the ridge as sled tracks were also observed. The large avalanche failed on sugary faceted snow near the ground.
In the past couple days, we could see blown-in evidence of fairly extensive natural storm and wind slab activity that occurred during the storm across the zone. Although pretty filled in by the deep powder, a few appeared to to have been fairly deep, likely running on a buried persistent weak layer. From a distance, I thought I could see a large crown from a natural deep slab avalanche on the east buttress of Mt. Gog on a drifted south-southeast facing slope.
This small natural avalanche of wind drifted snow above Tony Grove Lake occurred late in the storm.
On Monday, a natural avalanche on a west facing slope at about 7200' in elevation stopped just before hitting highway 89 in Beaver Canyon. A trail groomer in Bear Lake County reports remote triggering avalanches on hills he's never before seen slide before.
Last 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.
Avalanche Problem #1
Wind Drifted Snow
Type
Location
Likelihood
Size
Description
South winds increased significantly yesterday and continued to blow overnight, drifting tons of nice powder into lee slope avalanche starting zones. Large natural avalanches are possible, and people are likely to trigger avalanches of wind drifted snow on many upper and mid elevation slopes. Avalanches are possible to trigger on some steep lower elevation slopes as well. Some avalanches could step down into buried persistent weak layers, involve large volumes of snow, and run fast and far.
- 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.
- 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 drifted 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. South facing, wind scoured, rocky, and mid and lower elevation slopes with shallow snow cover are plagued by sugary, faceted snow, now deeply buried by feet of fresh powder. The additional weight from the recent snow and drifting could be enough to reactivate a deeply buried persistent weak layer on some north and east facing slopes.
The fresh avalanche in the Rodeo Grounds appears to have failed on sugary faceted snow near the ground.
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.
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.
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.