Avalanche forecast

Avalanche forecast

Payette Avalanche Center
View on map

Avalanche danger

Sun
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Out of date — this forecast expired 5 years ago.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 still possible across our advisory area today in steep and wind-affected terrain. Some slopes or solar aspects have the last 5-10 inches of new snow resting on a slick crust.

Watch for deeper pockets of wind-driven snow(wind slabs) on leeward ridges and terrain features.  Some areas may still be harboring layers of faceted snow that developed during the clear nights of our extended high pressure.

Pay attention to visual clues of wind-affected snow such as 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

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    This week's snow came in with a fair amount of wind.  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. Some of these wind slabs may be resting on preserved layers of near-surface facets or surface hoar.  You are likely to find wind slabs on several aspects based on the variability of the wind over the last few days.  

    (2/18/2022)

    Granite Mountain, Twin Lakes Ridge...North winds during the last storm pushed the snow to the South (from right to left in the photo) creating 2 foot deep pillows that we were unable to get any cracking from

    Photo: GH

  • Loose Dry

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

    Small loose dry avalanches or sluffs could run with you in steep terrain. The last storm put down around 5 inches throughout most of our advisory area and more snow in the Northern portion of the advisory area, around 8 inches.

    In steep, exposed terrain, especially terrain traps like gullies and cliffs this might be a problem big enough to consider...aka steep terrain sluff management.  More than likely this will only be a problem in shaded terrain steeper than 38 degrees where the loose dry snow could push you into terrain you would like to avoid. 

Avalanche Discussion

Today's advisory is sponsored by OnXBackcountry gps map app...Thank you for supporting the Friends and the PAC!

5 weeks of high pressure can do a lot of damage to the snowpack, forming weak layers and crusts on the surface not just from the Sun, but also from record high temps that formed crusts on even cool North aspects.  Some South-facing ridges are bare, but we still have anywhere from a 6-8 feet deep snowpack in the upper elevations. We have 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.  

 -Surface Hoar and Near Surface Facets were formed throughout the high pressure at the snow surface and have persisted in some shady, wind-protected areas.   These layers are now buried in the upper portion of the snowpack. By the looks of the crystals, these layers may do a good job stabilizing....right now tests are hard, but the slab above is still 4 finger or soft, and which dampens the energy for propagating on these weak layers. As the slab above gains density results could get easier.

-Last week saw some of the warmest temperatures of the winter and left us with widespread crusts.  The new snow we got earlier this week 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 wind deposited snow. 

-We have another significant storm system lined up later this Sunday and Monday and the possibility of more next week.  Adding more snow and another round of gusty winds is going to increase the density and the size of the slab growing above our problem layers.  Avalanche activity will increase with these storms as will the likelihood of human-triggered avalanches.  It is going to be important to adjust your perception of the snowpack and your travel practices to these changing conditions.