Avalanche forecast

Silver Valley & Bitterroot Mountains

Idaho Panhandle Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 3 years ago.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

Highlights

The avalanche danger will remain HIGH on Wednesday at upper elevations.  Fresh wind slabs have been created on northwest to northeast facing slopes at upper and mid elevations and will be easily triggered today. Lookout for signs of instability such as cracking underfoot. Good skiing and riding can be found in low angle terrain that is sheltered by the trees. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    1–2.5

    The recent storm delivered a much needed refresh with as much as 20" of light snow, with additional snow continuing to fall throughout the day on Tuesday and Tuesday night. This new snow was accompanied by strong winds, 30mph with gusts near 60mph, consistently blowing from the southwest. With plenty of snow available for transport, reactive wind slabs will form below ridgelines and cross load terrain features like gullies. Stay aware of wind loaded areas and density changes underfoot and seek lower angle skiing and riding if you experience shooting cracks under your skis or snowmobile. 

    Additional snowfall and winds will accompany an approaching cold front on Thursday. This will add to the wind slab issue and create some bitterly cold conditions across the area into the weekend.

  • Persistent Slabs

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

    A new layer of surface hoar formed on 1/1 and was buried intact by the most recent storm cycle.  This buried surface hoar was preserved on less sun affected slopes and can be found intact on north facing aspects. We have also found a weak layer of facets above the December 20th rain crust. Deeper in the snowpack, the late November surface hoar is harder to find and less reactive in isolated areas on north facing slopes, but we are not ruling it out until we see evidence that it is no longer a threat. With the new snow load, these persistent weak layers have the potential to become activated. We should treat them with respect until we find evidence that they are no longer a problem. 

Avalanche Discussion

Avy Techs Brian and Izzy toured around Burk Summit yesterday. They found that the new snow, although stable, was light density and vulnerable to changing weather conditions we are seeing. Yesterday's pit tests showed relative stability as new snow has come in "right-side up", but continued loading with additional snow and wind throughout the day will see conditions change and avalanche danger increase.

New snow makes for great skiing, but it's an opportunity to take a step back and make good decisions. Be careful and avoid steep areas where the winds have hit hard. Very windy conditions from the Southwest will have the potential for consequential avalanches in the upcoming days. This is our greatest concern and will be found in specific locations, such as below the leeward side of ridges or in cross loaded gullies. Even after winds die down, evidence of intense winds effected the snow is indicated by cracking snow, chalky hollow feeling snow that should be avoided in and around avalanche terrain. Wind slabs can be avoided by sticking to sheltered or wind-scoured areas. 

At mid to upper elevations, we've got double header Avalanche problems: strong winds out of the Southwest and persistent weak layers. IPAC has issued an avalanche warning as avalanche danger is likely to rise between publication of this forecast and by the time it expires.

Sometimes, when it’s blowing snow, the best thing to do is talk about it over a beverage with your backcountry friends and wait till the next chance you can get together for better conditions. Stay safe if you are going out and look for signs of instability! Especially near wind affected areas.

Special Notes: This weekend, The Friends of Idaho Panhandle Avalanche Center only has a few spots left for the Motorized Level 1 Avalanche Safety Course in the Silver Valley. The course consists of two portions: an online classroom followed by two days (Saturday and Sunday) in the backcountry near the Silver Valley. Students will receive a certificate upon completion of the field days. Sign up fast and learn from the pros “1 on 1!”  

Shout out to Essex P. , Sean M., and Ari K. for their Observations throughout the Valley. We appreciate the info. 

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