Bulletin d’avalanche

Logan

Utah Avalanche Center
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Danger d’avalanche

  • Alpin
  • Limite forestière
  • Sous la limite forestière
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Périmé — ce bulletin a expiré 7 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Heavy snow and intensifying west winds in the afternoon will cause rising avalanche danger today. CONSIDERABLE danger exists on upper and mid elevation slopes, and people are likely to trigger avalanches of wind drifted snow 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.

HIGH danger is likely to develop this afternoon on some drifted upper elevation slopes. Very dangerous conditions will become more widespread tonight, with large, fast moving, and long running natural avalanches quite possible.

  • Evaluate snow and terrain carefully. Use caution while route finding, and make conservative decisions.
  • Stay off and out from under steep wind drifted slopes. Avoid travel in avalanche terrain and stay clear of avalanche run out zones.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Very Likely
    Taille
    2

    People are likely to trigger 1.5 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.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    3

    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.

    We found stable but very weak sugary snow throughout the snowpack Thursday near the Spring Road at about 7500' on the Beaver Backside.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1

    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.

Recent Activity

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.

Snow and Weather

It's 15°F at the 8400' Tony Grove Snotel this morning, and there is 9 inches of new snow with .9" SWE from yesterday and overnight. The site also picked up a couple feet of new snow with 1.6" SWE Wednesday night and Thursday. There is 78 inches of total snow, with 123% of average SWE for the date. It's 7°F at the CSI weather station at 9700' on Logan Peak, and west winds are currently blowing about 20 mph. Today's heavy snowfall and drifting from increasing west winds will cause the avalanche danger to rise and become more widespread. Dangerous avalanche conditions already exist on some drifted upper and mid-elevation slopes. So, don't let your guard down.

Expect heavy snow in the mountains today, with 6 to 10 inches of accumulation possible. 8500' high temperatures will be around 17°F, west winds 15 to 20 mph increasing to 21 to 26 mph in the afternoon. Wind chill values will be around -6°F. Snowfall could be rather intense tonight, with 11 to 17 inches of accumulation possible! Low temperatures are expected to rise to around 21°F, with strong, 24 to 31 mph southwest winds, and wind chills around -11°F. Snow will continue tomorrow, with 4 to 8 inches possible, west-southwest winds 24 to 26 mph. Active and snowy weather is expected to continue through next week with colder than normal temperatures and several more storms in the forecast.

Additional Info

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.

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.

Régions couvertes