Avalanche forecast

Avalanche forecast

Payette Avalanche Center
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Avalanche danger

Fri
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
Out of date — this forecast expired 5 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Human triggered avalanches are possible across our advisory area today.  Storm totals at the ski resorts and at our local snotel sites don't show it but upper elevations received 4-8 inches of snow accompanied by gusty winds.  Accumulation totals and the thickness of storm and wind slabs will vary quite a bit from slope to slope but slick crusts are widespread beneath the new snow and will provide an easy sliding surface if you do trigger a cohesive slab.  Watch for deep pockets of wind-driven snow(wind slabs) on leeward ridges and terrain features. Dry loose avalanches (sluffs) will be easy to trigger and should be anticipated on all steep terrain today.  Pay attention to visual clues like drifts, pillows, and texture changes in the snow surface, and don't ignore red flag signs like cracking of the snow surface as you travel.

Avalanche problems

  • Loose Dry

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–1.5

    With solar and melt/freeze crusts being VERY widespread after last week's warm temps, the new snow is not bonding to these slick crusts and will want to run or sluff with you on any steep slope.   Even dry snow sluffs can surprise you, push you off your line, or pile up deep in terrain traps, your best bet today is to avoid steeper terrain.

    NNE hasty pit near 8000'

    Melt/Freeze crust layer(at card) from the very warm weather we experienced last weekend.  Crusts are widespread on all aspects below the new snow.  Weak, faceted snow is still present below the crust(saw) in many places.

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    Winds gusted most of the day yesterday and last night into the mid to upper 20's and were able to easily move the new snow around. Wind slabs are going to be fairly widespread in wind-exposed terrain today,  these slabs may be fairly dense or on the soft side.  Based on the slick crust below them though, they may be easy to trigger, propagate easily across the curst, pick up or entrain more snow below them and run fairly fast if you do trigger them.  We found wind slabs on several aspects yesterday and on subtle terrain features that were able to catch the wind-driven snow.  These slabs may range in thickness from 10 inches to several feet like the one pictured here.

    Deep pillows of denser snow can be found on even subtle leeward terrain features. These wind slabs are more widespread near ridgelines.

Avalanche Discussion

Today's advisory is sponsored by Brundage Mountain Resort, a huge thanks for supporting the Friends and PAC!

5 weeks of high pressure can do a lot of damage to the snowpack.  We have actually been pretty lucky that we were able to maintain some protected pockets of soft snow and had a few little shots of fresh snow when conditions got pretty bad. We have also been lucky that conditions allowed users to get into steep and committing terrain with very low avalanche hazard through most of the winter so far.  Last week saw some of the warmest temperatures of the winter and left us with widespread crusts.  The new snow isn't sticking to these crusts.   In most places, we are talking about a pretty shallow and unconsolidated slab of new snow above the crusts but in some spots, you will find deep drifts or pillows of denser, cohesive snow.  In addition to the fact that these deeper wind slabs are sitting on the slick crust, our pit tests yesterday showed propagation in both Compression and Extended Column tests and easy/low scores failing on the crust. This is the first time this winter that we have seen easy propagation results in our local snowpack which should make you carefully consider your terrain choices.  With winds still gusting enough to transport the new snow today, weak layers in place, and additional snowfall coming this weekend, it is time to hit the reset on your mental picture of the snowpack and the anything-goes travel attitudes that we have had so far this winter.