Avalanche forecast

Avalanche forecast

Payette Avalanche Center
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Avalanche danger

Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
Out of date — this forecast expired 6 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

The Avalanche Hazard in the West Central Mountains will rise to CONSIDERABLE today as a significant storm adds weight to the snowpack.  Triggering a new storm slab or recently formed wind slab will become more likely through the day as storm and windblown snow are piling up. Older, persistent weak layers are generally becoming harder to trigger and in many areas and are becoming less of a concern, this storm will test them. These older slabs range between a few inches and over 2 feet depending on where you are and will be growing today.   Because of the variability of the wind and weather over the last few days and the distribution of weak layers throughout our forecast area, cautious terrain selection is still your best bet.  2 human triggered avalanches have been reported in persistent weak layers in the Lick Creek Area in the last 2 days. 

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2

    There is a bit of disagreement in the weather models and forecasts today, the Boise NWS has issued a Winter Storm Advisory while the Missoula NWS office has issued a Winter Storm Warning just to the north.   Snow totals will be significant and some areas of the PAC advisory areas will see significant wind accompanying the storm.  Temperatures will also be rising through the day today which means we have warmer snow falling on the cold snow that fell over the last 2 days.  Expect to see increasing avalanche hazard throughout the day as the new snow and windblown snow accumulate and form new storm and wind slabs.  We still have a variety of weak layers in our snowpack and adding weight to them will give them a stability test over the next 24 hours.  Adding your weight to the equation may be just enough to tip the scales.

    This forecast shows potential for 8-10+ inches of snow by 4 pm today.

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Winds have been gusting from the southern portion of the compass over the last 5 days, and have created wind slabs in leeward terrain. Yesterday the winds swirled around to the NE and NW.  Winds will be increasing again today and will have plenty of fresh snow to move around.  Expect to see growing wind slabs on all upper elevation and exposed terrain.

    Terrain can influence wind loading differently from slope to slope and even across micro features on a slope.  Watch for stiff drifts and wind slabs on leeward terrain even well below the ridgetops. Avoid natural terrain traps like gullies.  Pay attention to the consistency and density of the snow under your skis, sled, or moto while you travel through different terrain.  A sudden change in the surface of the snow is a good indicator of wind slab formation.

      

     

    Pit from 2/3/21 near the top of Wildwood Bowl in a wind-affected area. This layer is resting on a weaker layer below it and was reactive in ski cuts.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–3

    The mountains received over 2 feet of new snow over the last week.  We now have a soft slab about 2-2.5 feet deep that formed over weaker snow and crusts below, which was the cause of the avalanche cycle last week. 2 skier triggered avalanches have occurred in the last 2 days at the new/old snow interface. Both of the reporting parties described easy and rapid propagation over a large area on a slick crust. Triggering this slab is getting harder as it is gaining strength but avoiding steep terrain and only putting one person at a time on a slope is still your best bet.  Adding the weight of new snow to these weak layers will be a test of the strength of them, expect to see natural and human-caused avalanches as the snow piles up today and tonight. 

     

    (2/4/2021) 2 skier triggered avalanches have occurred in this area in the last 2 days. The bed surface was a slick crust. 2 skiers were caught and one skier was partially buried in this slide yesterday.

Avalanche Discussion

There are multiple buried weak layers and crust/facet combinations in the upper portion of our snowpack right now. The addition of new and windblown snow on these layers is providing ample reasons to be cautious.   Today's storm has the potential to put a significant strain on the snowpack, including deeper, weak layers.  Expect to see increasing avalanche hazard throughout the day today and plan your routes accordingly over the next few days. New snow and wind-blown snow will be falling on a variety of old snow surfaces including some very slick crusts that will make it easy to trigger storm slabs as the new snow piles up. 

If you see or trigger avalanche activity, please take the time to snap a picture and note the approximate elevation and aspect, you can submit an observation on our website. Getting your info helps forecasters and other users get a better picture of the conditions throughout our mountains. If you have trouble using our observations page, email us at: [email protected].

*Also, Please be mindful of other users, and where you are at. There are closures for motorized travel in and around the local ski areas, Granite Mtn, and other areas throughout our region.

***Check out the Winter Travel Map to find out where you can shred on your sled or moto.