Avalanche forecast

Avalanche forecast

Payette Avalanche Center
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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Out of date — this forecast expired 5 years ago.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

Buried weak layers are gaining strength...Winds have calmed and slabs should be stabilizing.

Be cautious in steep terrain, and only expose one person at a time. Early-season obstacles like rocks and logs exist at mid and low elevations.

 

Avalanche problems

  • Persistent Slabs

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

    Our snowpack is consolidating and getting stronger. It is dense at the bottom and graduates softer as you get towards the surface. On December 12th an atmospheric river event began, and ultimately doubled our snowpack...now a slab has developed above the snow that was on the ground from October to December 12th and is showing moderate test scores. At that interface when we look on at the facets under a hand lens the facets are rounding and clustered. We will continue to monitor the strength of this layer as it is definitely shallow enough to be affected by the weight of humans.

  • Wind Slabs

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

    The winds have started to wind down enough that it is likely that most slabs that have developed early in the week have had just enough time to bond. I would not rule out the possibility of triggering an isolated wind slab in steep terrain above 7,000 feet. Just below ridges and below cornices are the most likely spots to trigger wind slabs.

    Even though most of the winds in the last few days have been out of the South, the snow has been very light in density, and easily transportable...local terrain can influence the direction of loading as well as increase the windspeed and load leeward slopes even though the surrounding winds are light.

Avalanche Discussion

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While avalanche problems are serious, early season conditions/ buried obstacles are still serious threats to Snowmobilers and skiers. Coverage at elevations above 7,000 feet is good enough to allow some travel, but most of the terrain still has a lot of rocks, logs and bushes showing. The snowpack is growing in depth (150-180 cm at 7500ft), and weak layers of crusts and facets are showing (rounding) progress towards stabilization.  Our snowpack that formed from October-early December is gone on lower elevation slopes that got hit by a record warmup and Sun.  North aspects are still holding that Oct-Dec snow that is between 1-2 feet near the ground. 

If you are going to ski or ride a steep upper elevation slope, only expose one person at a time. Snowmobiling off-trail is super high stakes right now with the shallow snow and all of the obstacles needing to be buried....be extra careful.

Recent cold temperatures have helped to break down crusts and deposit some of the best light-density snow that would make most people smile. While our snowpack is trending deeper and stronger, the snowpack is still shallow below 7500 feet and there are a lot of hazards lurking just beneath the surface. Above 7, 500 feet there is around 5 feet of snow on the ground, and in wind-loaded terrain some slopes could have around 8-10 feet of snow.   Shallow snow is not only easy to hit obstacles in, but it allows skiers and riders to have more effect on buried weak layers.

 Things are looking good, but allow room for error as there is a lot of variability in our mountains right now.