Forecast for the Logan Area Mountains
Issued by Toby Weed on
Saturday morning, January 18, 2020
Saturday morning, January 18, 2020
Yesterday's very strong westerly winds created CONSIDERABLE danger on drifted upper and mid elevation slopes. Dangerous conditions exist in the backcountry today, and people are likely to trigger avalanches of wind drifted snow. Avalanches are possible at all elevations, 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 or under steep drifted slopes.
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Moderate
Considerable
High
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Weather and Snow
It's 12°F at the 8400' Tony Grove Snotel this morning where yesterday's fast storm dropped a foot of new snow with 1.0" Snow Water Equivalent in just a couple hours. There is 89 inches of total snow at the site. It's 9°F at the CSI weather station at 9700' on Logan Peak, and winds from the west-southwest are currently blowing around 25 mph.
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. Strong south winds Thursday and west winds yesterday drifted the deep powder in exposed terrain, ripping it off windward facing slopes or fetch areas and depositing it into lee slope deposition areas. Dangerous avalanche conditions exist now on drifted upper and mid-elevation slopes, with human triggered avalanches likely.
Today will be partly sunny, with 8500' high temperatures around 24°F, 9 to 17 mph west winds, and wind chills around -15 °F. It'll be mostly clear tonight, with low temperatures around 8°F, 9 to 11 mph west winds, and wind chills around -6°F. Expect sunny weather tomorrow, with high temperatures around 28°F, southwest winds 5 to 8 mph, and wind chills around 0°F.
Although there is still a fair amount of uncertainty, active weather looks to return around 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. This video contains preliminary information collected during the site investigation; a full accident report will be published soon.
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.
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.
Avalanche Problem #1
Wind Drifted Snow
Type
Location
Likelihood
Size
Description
Strong south and west winds drifted tons of last week's nice powder into lee slope avalanche starting zones. Today, 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 be quite dangerous and destructive.
- 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, in others a layer of surface hoar feathers was buried by the New Years Storm. Slopes with previously shallow snow cover are plagued by weak and sugary faceted snow. The additional weight from feet of recent snow and yesterday's drifting could be enough to activate the deeply buried persistent weak layer on some upper elevation slopes.
- Some avalanches might be triggered remotely, from a distance or below.
- Smaller avalanches overrunning a slope with buried persistent weak layers could step down into old snow and initiate a much larger avalanche.
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.