Avalanche forecast

Central Cascades

Central Oregon Avalanche Center
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Avalanche danger

Mon
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Slab avalanches will be likely on Sunday due to recent storm snow and wind drifted snow. Large to very large avalanches within old snow will also be possible. Use caution near and above treeline, especially if you observe any cracking, whumpfing or recent avalanches. If you see signs of instability, move to slopes lower than 30 degrees. 

Avalanche problems

  • Wind Slabs

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

    On Saturday, we found wind slabs to be reactive on northerly aspects near treeline. With more snow forecasted Saturday night and moderate winds, human triggered wind slabs will be likely. Wind slabs will be found near and above treeline on N, NE, E, SE and S aspects.

    Look for clues of wind slabs such as drifted snow, textured snow surface and cracking. These slabs can be found near ridgelines, features that collect snow, and areas where snow can move freely from wind (i.e burn areas). Finding safe "test slopes" to stomp on can give you good information regarding wind slab formation and distribution. If traveling in and near avalanche terrain, use careful routefinding and conservative decision making on Sunday.

     

  • Storm Slabs

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

    On Sunday we found storm slabs near treeline at Tam McArthur Rim, and they were easy to trigger. These slabs were about 6"-8" deep, propagated further than expected, and were fracturing within the new storm snow. We did not find these slabs everywhere, but be mindful of this avalanche problem especially in steep terrain and above terrain traps (cliffs, gulley, trees). Similiar storm slabs were also reported near Santiam Pass. 

    Look for clues of storm slabs such as cracking, recent avalanches, and consider using safe test slopes to assess the snow. Storm slabs tend to form in sheltered areas and usually stabilize after a day or two.

     

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–3

    We have been tracking a few buried weak layers (facets and buried surface hoar) within our snowpack. With significant new snow amounts, these layers are buried down 3-6' deep. Earlier in the week forecasters found an avalanche on a faceted layer that broke 3' down. We have not observed avalanches on this layer in the past few days, but that is the tricky part of this problem. As these layers become deeper, they become more difficult to trigger, and we often do not receive much feedback (such as whumfing and collapses). However, if this layer does release, it will likely be large to very large.  This avalanche type can suprise riders as it can be remotely triggered and fracture much farther than expected.

Avalanche Discussion

Sunday we will see improving weather and it will be tempting to head to higher elevations. Use conservative decision making if you choose to venture to higher elevations and larger terrain features. It is best to give the snow some time to settle.

Regions covered