Bollettino valanghe

Logan

Utah Avalanche Center
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Pericolo valanghe

  • Alta quota
  • Limite del bosco
  • Sotto il limite del bosco
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In sintesi

Dangerous avalanche conditions exist in the backcountry, and there's CONSIDERABLE danger on drifted upper and mid elevation slopes. People are likely to trigger avalanches of wind drifted snow, and natural avalanches are possible. Some avalanches could fail on a buried persistent weak layer and be large, fast moving and long running. Instabilities within new snow tend to stabilize fairly quickly, but soft slab and loose avalanches of new snow are still likely today on many steep slopes and possible at all elevations.

  • 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.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Very Likely
    Dimensione
    2

    People are likely to trigger avalanches of wind drifted snow on many upper and mid elevation slopes. Avalanches are possible to trigger on many 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.

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    3

    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. All the additional weight from the recent snow could be enough to reactivate a deeply buried persistent weak layer on some north facing slopes.

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Very Likely
    Dimensione
    2

    Although we expect the deep new snow to stabilize fairly quickly, human triggered loose sluffs and soft slabs of drifted new snow are still likely today on steep slopes at all elevations. Avalanches of powder snow can move fast and run far. Even small avalanches can be quite dangerous and become unmanageable if you get dragged into trees or other terrain traps below.

    It was easy for people to trigger storm slabs of drifted new snow yesterday in exposed mid elevation terrain.

Recent Activity

During the storm, natural avalanches of new and drifted snow occurred at all elevations. Few people made it out into the backcountry yesterday, but we did get a report of easily triggered storm slabs in exposed mid elevation terrain (S and SW facing) above southern Cache Valley.

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.

A natural avalanche started in the forest and stopped just above highway 89 in Beaver Canyon. 1-13-2020.

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.

Snow and Weather

It's 15°F at the 8400' Tony Grove Snotel this morning, and there is another 14 inches of new snow with 1.3" Snow Water Equivalent from yesterday and overnight. There is 96 inches of total snow, with 134% of average SWE for the date. The station reports 5.7" SWE in the last week, since Wednesday (1-8-20). It's 8°F at the CSI weather station at 9700' on Logan Peak, and west-southwest winds are diminishing a bit, currently blowing about 20 mph. Dangerous avalanche conditions exist on drifted upper and mid-elevation slopes. Heavy snowfall and strong southwest winds created CONSIDERABLE avalanche danger, with human triggered avalanches likely, and fast moving and long running natural avalanches possible. More snow fell in the northern part of the Logan Zone, and dangerous conditions are a bit more widespread around and north of the state line.

Expect partly sunny skies today, 8500' high temperatures will be around 23°F, west-northwest winds 11 to 14 mph, and wind chill values will be around -7°F. It'll be mostly cloudy tonight, with low temperatures in the teens, with increasing, 14 to 22 mph south winds, and wind chills around -5°F. Tomorrow will be partly sunny and rather mild, with a high near 32°F. It will be windy, with a south wind 23 to 26 mph. Another potent storm is expected to impact the area Thursday night into Friday.

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.

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