Avalanche forecast

Logan

Utah Avalanche Center
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Avalanche danger

  • Alpine
  • Treeline
  • Below treeline
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Highlights

Areas with CONSIDERABLE danger exist on high north facing slopes in the backcountry. Drifting and heavy snow overloaded slopes plagued by a deeply buried persistent weak layer, and people could trigger dangerous avalanches breaking 4 to 6 feet deep on sugary faceted snow near the ground. Heightened conditions also exist in steep drifted mid and upper elevation terrain, and avalanches of wind drifted snow are possible on slopes facing any direction. Colder temperatures last night and today are solidly refreezing the loose saturated snow at lower elevations and rapidly increasing stability, so the danger is low and wet avalanches are unlikely.

  • Evaluate snow and terrain carefully, and make conservative decisions.
  • I'm still avoiding steep north facing slopes at upper elevations where a person could trigger a dangerous deep slab avalanche breaking on a persistent weak layer near the ground.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    3

    Although they have become less likely and harder to trigger, very dangerous deep hard slab avalanches remain possible. The rapid load from this week's new snow, and especially from continued drifting, could be enough increase in load to cause dangerous natural hard slab avalanches failing on a deeply buried persistent weak layer on upper elevation northerly facing slopes. These slopes have a layer of weak, sugary facets near the ground that could fracture and produce slab avalanches 4-6 feet deep and hundreds of feet across. The danger of deep slab avalanches failing on a persistent weak layer is diminishing as the snow pack continues to deepen and get heavier, and the sugary faceted snow is compressed into the ground features. However is some areas, avalanches on northerly facing slopes still might be triggered remotely, from a distance, or from flatter terrain under steep slopes.

    • Recent strong winds drifted snow right onto suspect northerly facing slopes that are plagued by a persistent weak layer, increasing the load and the danger.
    • An avalanche of wind drifted snow overrunning a slope with a deeply buried persistent weak layer could step down, include older snow, and become much larger and more destructive. Here is a more in depth discussion with UAC staff about persistent weak layers and slowly dropping danger ratings..

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2

    People could trigger slab avalanches of wind drifted snow in steep terrain at mid and upper elevations today. Winds finally moderated last night and veered from the northwest after days of blowing very strongly from the south and west, raking the fresh snow off windward slopes and depositing it in stiff drifts on the lee side of major ridges and in and around terrain features. Wind slabs and cornices will not be as sensitive today, and some could let a person get out on them before releasing like a mouse trap.

    • Large cornices could break further back than you expect, so you should stay well away from them, passing on the windward side of the ridge.
    • Cornice-falls could overload drifted slopes below and trigger large avalanches.
    • Avoid cornices and deposits of wind drifted snow in and around terrain features like sub-ridges, gullies, scoops, and cliff bands.

Recent Activity

Numerous natural loose wet avalanches, entraining big piles of heavy snow occurred in Logan Canyon Thursday afternoon.

Heavy snow and wind drifting caused many natural avalanches to occur during this week's storm across the zone. Yesterday, I could see evidence of recent avalanche activity in most of the east facing avalanche paths in the Wellsville Range.

Check HERE for all the latest observations and avalanche activity.

Snow and Weather

About three feet of very heavy snow accumulated at upper elevations with this week's windy, wet, and warm storm. The 8400' Tony Grove Snotel reports a much cooler 20°F this morning and a couple inches of new snow. There is 84 inches of total snow. This week's storm deposited over 8"of SWE (snow water equivalent) at the site between Tuesday morning and Thursday night, which is an amazing amount. Winds out of the northwest are blowing around 25 mph, with gusts around 45 mph at the CSI Logan Peak weather station. Clearing and fair weather is expected to build over the region starting tonight, continuing well into the middle of next week.

It rained on the snow down low, saturating the snowpack to the ground and creating runnels across the snow surface on all the slopes in mid Logan Canyon.

Carly sent in this picture of intense rain channeling on a slope in lower Bunch Grass. All slopes in the area now look like this....

Additional Info

  • Always follow safe backcountry travel protocols. Go one person at a time in avalanche terrain, while the rest of your party watches from a safe area.
  • Check your avalanche rescue equipment, change your batteries, and practice often with your backcountry partners. Check slope angles and stay off of and out from under slopes steeper than 30° and adjacent slopes.

General Announcements

Who's up for some free avalanche training? Get a refresher, become better prepared for an upcoming avalanche class, or just boost your skills. Go to https://learn.kbyg.org/ and scroll down to Step 2 for a series of interactive online avalanche courses produced by the UAC.

  • Check out all the upcoming education classes and clinics HERE.
  • Please submit your observations from the backcountry HERE.

This information does not apply to developed ski areas or highways where avalanche control is normally done. This forecast is from the U.S.D.A. Forest Service, which is solely responsible for its content. This forecast describes general avalanche conditions and local variations always occur.

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