Lawinenlagebericht

Blues

Wallowa Avalanche Center
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Lawinengefahr

Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Kernpunkte

It will be possible to trigger an avalanche today as winds pick up and transport snow onto the leeward side of ridgelines and cross-load mid-slope terrain features.  It is still possible to trigger a deeper and more destructive avalanche in persistent weak layers buried 2-3' 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 CB Construction, Inc. 

Lawinenprobleme

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Unlikely
    Größe
    1–2

    We are still finding poor snowpack structure in the Blues, although it is unlikely you would trigger a persistent slab, it is not impossible.  We continue to be in the realm of the low-probability, high-consequence persistent slab problem.  Triggering one of these slides would have serious consequences. The November/December facets are capped by a thick crust and beginning to bond but are still substantially weaker than the snow above and below them. This creates the recipe for an avalanche. 

     

     

    (2/7/2024)

    Column failed 100cm down where the saw is stuck in the snow.

    Photo: Nick Burks

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–1.5

    Increasing winds today out of the South and Southwest will blow surface snow onto leeward slopes and cross-load mid-slope terrain features.  These wind slab avalanches could break up to a foot deep.

    Look for clues of windslab development such as cornices along ridgelines, a rippled texture on the snow surface, and a stiff feel to the snow under your machine or boards.  

    Avoid terrain that has been recently wind-loaded. 

    (1/11/2024)

    Rippled Snow Surface and Cracking are good indications of wind slab development. 

    Photo: Caleb Merrill

Avalanche Discussion

The persistent slab problem continues to plague the Blue Mountains. There are weak layers toward the bottom of the snowpack that still remain reactive. Recreationsist 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 is falling on a variable and weak old snow surface. This will create instabilities at the old/new interface. Where storm totals are around 6" or less 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). 

A big issue out there is that we had widespread surface hoar formation during the recent dry spell and cold clear nights. 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. Not a good situation.  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 propogate 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. 

 

 

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