Avalanche forecast

Southern Wallowas

Wallowa Avalanche Center
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Avalanche danger

Fri
Alpine
4 · High
Treeline
4 · High
Below
2 · Moderate
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Out of date — this forecast expired 3 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

It remains likely that you could trigger a large deadly avalanche failing on weak snow 2-6 feet deep.  Large natural avalanches have occurred in the last 5 days.  Avoid riding slopes greater than 30 degrees, avoid riding above terrain traps, and stay out of avalanche runout zones.  The snowpack has been talking to us, and we should listen.  

Avalanches will be more likely around Fish Lake, Sugarloaf, Clear Creek Cabin, Norway Basin, and adjacent drainages where the past week's snowfall has been more substantial than that of the Southwestern Wallowas (Catherine Creek Snopark Area).  

This forecast is sponsored by Brooks Painting. 

Avalanche problems

  • Persistent Slabs

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

    The snowpack structure in the Southern Wallowas is poor and was overloaded by 5" of snow water equivalent over the past week.  The new snow load and wind blown snow produced many large natural avalanches.  The proof is in the pudding as they say.  Simmons Ridge near the Norway Yurt produced a large D2.5 natural avalanche sometime on Sunday 1/21.  Willie Sloop and Natalie Flower of WAH observed this, and you can read more from their observation here.   

    More observations of many natural avalanches with crown depths of up to 6 feet deep have trickled in from WAH guides yesterday in the Cornucopia/Norway basin area.  Observation elevations ranged from 4800-7800'.  Check them out here.

    Forecasters rode up to Fish Lake yesterday, and despite having limited visibility, it was impossible not to see the large D2.5 natural avalanche that ran across FS RD 66 in an area locals call Avalanche Alley.  (6800' NE aspect).  The crown of this avalanche was 4 feet deep and failed on small-grained faceted snow that sat above a thin crust.  Check out the observation from yesterday here. We also observed the toe of the debris from a large natural avalanche that reached the elevation of Fish Lake (East aspect).  

    Recent natural and remotely triggered avalanches should be all of the bulls-eye data you need to dial back your terrain choices.  If you want to avoid avalanches, you should stay off of slopes greater than 30 degrees, stay well clear of avalanche runout zones, and not ride above terrain traps.  Don't trust these facets until they are swimming in the river!  

     

    (1/24/2024)

    This large natural avalanche occured in a zone local riders call "avalanche alley" and put 3-4 feet of debris on FS rd. 66 on the way into Fish Lake.  If you were sitting on your machine on the road when this occured, you probably would have been killed.  The debris ran into the creek bottom below the road, damaging trees along its path.  

    Photo: Caleb Merrill

  • Wind Slabs

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

    Recent snowfall over the last week has been accompanied by some large temperature swings and moderate to strong winds.  This has created sensitive wind slabs in exposed area, and sensitive storm slabs in protected areas.  Cracking was observed yesterday along ridgelines.  Look for clues of windloading such as cornices and textured/stiff snow under your machine or boards.   Use small, inconsequential test slopes to test the reactivity of the new and wind blown snow. 

    Step above the skintrack and see if you can break a soft stormslab onto the skintrack.  Use hand pits to isolate a foot x foot column and pull on the back of it with your arm.  If you are getting clean breaks within the upper two feet of the snowpack, a storm slab is still possible.  Triggering a wind slab or storm slab avalanche could easily put enough weight on the snowpack that a deeper, more destructive persistent slab avalanche could subsequently occur.  

    Photo: WAH

    Cornices and wind slab development have been observed on leeward ridgelines and cross-loaded terrain features.  

Avalanche Discussion

Widespread natural avalanche cycles should be all the evidence you need to dial it back! 

As the 4-6 foot slab continues to strengthen and become even more cohesive, the weak sugar snow lurking near the bottom of the snowpack will continue to be a real threat.  In some areas, it is becoming less evident if you just look at the snow surface, as obvious signs of instability may not be present in all areas.  The cracking and whumphing (collapsing) that we observed last week has decreased, and as time progresses, the slab may be able to hold the weight of a rider until the slab thickness decreases somewhere in the terrain.   

Seeing tracks on a slope does not mean it is safe to ride.  Persistent slabs are notorious for allowing unsuspecting riders to lay numerous tracks without incident before one unlucky rider finds a thin spot in the snowpack, collapsing the weak layer and creating a large, destructive avalanche.  Common thin spots in the snow often develop around rocky steep rollovers, or where the wind has stripped snow from the up-wind (windward) sides of ridgelines. 

Now is not the time to push the terrain.  Patience is the name of the game with persistent slabs.  Read the forecast in its entirety, make a conservative travel plan that allows for wide terrain margins, use clear communication with your partners, listen to your gut, and speak up.  

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