Avalanche forecast

Avalanche forecast

Payette Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 5 years ago.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

Highlights

The Avalanche Hazard is Moderate today in wind exposed terrain.  You are likely to encounter newly formed wind slabs near ridgetops and in leeward terrain.  Winds have shifted around the compass from SW to NW over the last 48 hours so you may find wind slabs on multiple aspects ranging from a few inches to close to 2 feet thick. Wind speeds peaked yesterday morning at the Granite Weather Station at 32 mph which was ample wind to transport the light density snow that we have been getting this week.  Lower elevation, protected aspects have generally stable conditions but several weak layers are distributed in these areas.  Until we see significant accumulations, these layers are unlikely to produce avalanches or will be confined to small slabs in the upper 10 inches of the snowpack.  Riding and sliding conditions are improving although there are still some lingering areas of breakable crust on the solar aspects. Use good travel protocols especially in steeper terrain.

Avalanche problems

  • Wind Slabs

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

    Winds speeds have gusted into the upper 20 mph range this week and yesterday gusts peaked at 32 mph.  These wind speeds were more than adequate to move the 11 inches of light density snow we have received this week around. Most of these slabs are confined to areas near ridgetops but are widely dispersed on multiple aspects.  You are more likely to trigger these slabs near ridgetops or just below them on steeper terrain.  In addition to the wind slabs, you are likely to find a very stout windboard( crust) near the ridgetops or on prominent sub ridges that were exposed to the higher velocity wind gusts.  Visual clues are easy to pick up and some of these slabs had a distinctive hollow sound where we found them yesterday.

    Visual evidence of wind-affected snow on and near ridgetops. Etching, drifting, and sculpting are signs of wind slab formation.

Avalanche Discussion

Today's advisory is possible through the generosity of Brundage Mountain Resort, a huge thanks for their support of the Friends and the PAC!

This week's small storms have been a welcome addition to our snowpack and provided a great refresh to the riding andsliding conditions.  Lower angle, wind-protected slopes have plenty of soft snow on them and good snow can be found on upper elevation slopes that have been protected from the worst of the winds.  Ridgetop and near ridgetop conditions are a mixed bag and also where you are most likely to encounter wind slabs that will be touchy for skiers and snowmobilers. Most of these new wind slabs are relatively shallow but we were able to find some pockets that were getting close to 2 feet thick yesterday.  Without much new snow in the forecast and a return to high pressure, these slabs should start to stabilize over the next few days.  

Protected areas are holding the best snow but also are accumulating weak layers that are slowly getting buried.  You will find a layer of mixed type, faceted, snow 4-6 inches down and a layer of large grauple below the new storm snow (around 10 inches down).  We also found a non-reactive layer of grauple buried at around 24 inches down in the snowpack.

Even in lower hazard conditions, avalanches are still possible in specific locations,  good travel protocols and a one at a time policy on steeper slopes is your best insurance as you travel and play in the mountains.  

Also, as we all search for fresh snow please take a few minutes to review the Payette Winter Travel Map, there are some areas that are closed to motorized travel and are not signed.  It is your responsibility to know where these areas exist and respect closures for wildlife and non-motorized users.  Some of these closures are near Jughandle Mountain, Brundage Mountain Ski Resort, and Goose Lake, other closures exist in the Lick Creek Canyon.