Avalanche forecast

Elkhorns

Wallowa Avalanche Center
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Avalanche danger

Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

There remains the possibility of triggering wind slabs a foot thick or more at upper elevations on the leeward side of ridgelines and cross-loaded terrain features mid-slope.  It also remains possible to trigger a deeper and more destructive avalanche in persistent weak layers buried 2-6' deep in the snowpack.  To avoid avalanches, steer clear of terrain steeper than 30 degrees, wind-loaded slopes, and areas that harbor a shallow snowpack (less than 3 feet).  

This forecast is sponsored by Anthony Lakes Mountain Resort.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2.5

    The snowpacks in the Northern Wallowas and Northern Elkhorns are currently weaker than the other forecast zones. Despite the warm weather and rain in late January, poor snowpack structure still exists. The possibility of triggering a persistent slab avalanche is still a very real one. The slab of snow sitting above the weak layers has continued to gain cohesion over the last couple of weeks.  This means that if you were to trigger a persistent slab avalanche, it would propagate further and be larger than you might think. Triggering one of these avalanches would have serious consequences.

  • Wind Slabs

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

    The 8-10" of snow that fell on Thursday and Friday has been easily transported by SW winds and deposited on NW-E facing terrain at and below ridgelines. Moderate S  winds today will continue to move snow building larger wind slabs. Expect to find reactive wind slabs a foot or more thick. Riders should avoid slopes > 30 degrees where recent signs of wind-loading are evident. This includes areas below cornices and ridgelines on NW - N - E facing aspects and cross-loaded terrain mid-slope features.  Look for smooth pillows with a dabbled texture and if you get any shooting cracks or hollow-sounding snowpack underneath you, then you should stay off and out from underneath avalanche terrain.

     

    (1/13/2024) Photo: Caleb Merrill

Avalanche Discussion

The persistent slab problem continues to plague our northern zone. There are weak layers toward the bottom of the snowpack that remain reactive. Check out WAC forecaster, Caleb Merrill's observation from Mt. Howard a few days ago.  Recreationists should continue to be vigilant and seek out critical snowpack information to assess the reactivity of these deeply buried weak layers. The consequences of triggering an avalanche on these weak layers would be severe. 

The new storm snow (8-10") has fallen on a variable and weak old snow surface. This has likely created instabilities at the old/new interface. Where storm totals are around 6" or less, and/or the new snow remains cohesiveless, the main problem will be loose dry avalanches on slopes > 35 degrees. These small avalanches may not bury you, but they could inflict significant bodily harm if they were to take you off your feet or sled and sweep you into obstacles like rocks and trees. Where storm totals exceed 12" there will be a storm slab problem. The best practice for avoiding this problem is to stick to slopes < 30 degrees (i.e. stay out of avalanche terrain). 

There was widespread surface hoar formation before the Thursday- Friday storm arrived. Surface hoar is a notorious weak layer when buried. It can propagate fractures for long distances and while you may be on low-angle terrain, those fractures can propagate up onto a steep slope above you and release an avalanche. Likely locations for encountering buried surface hoar include more sheltered and protected slopes at and below treeline. If you are hearing the snowpack whoomph underneath you or seeing shooting cracks propagate outwards as you travel, then surface hoar is likely present at the old/new interface. This should have you dialing back your terrain choices and keeping off and out from under slopes > 30 degrees. 

Recent observations in the Elkhorns, Southern Wallowas, and Northern Wallowas paint a great picture of what this storm has left behind. 

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