Avalanche forecast

Central Cascades

Central Oregon Avalanche Center
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Avalanche danger

Tue
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

High temperatures and sunnier weather will continue to melt the snow and contribute to instability.  The greatest danger exists near and below Cornices which could fall off of ridgelines, and even trigger very large avalanches on weak layers deep in the snowpack.  Wet avalanches are increasingly likely as the day heats up, particularly on the sunniest and warmest slopes.

Avalanche problems

  • Cornices

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

    Avoid traveling near cornices and on slopes underneath large cornices.  Lots of rain over the weekend resulted in Cornice Falls.  Very high daytime temperatures, sunnier weather, and a lack of cold overnight temperatures all combine to mean that remaining cornices could easily collapse.

    Cornice collapses are especially dangerous right now as they could trigger very large avalanches on weak layers deep in our snowpack.

  • Loose Wet

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

    While rain from last weekend likely created the greatest instability in our snowpack (and that most dangerous period has passed), continuing very warm temperatures, sunnier skies, and a lack of cold overnight low temperatures means that wet instabilities will continue to be likely on Monday.  Wet slabs are decreasingly likely as the rain probably did the greatest damage, but Wet Slab considerations should not be entirely ruled out.

    Wet Loose avalanches are likely, particularly on steeper sunnier slopes.  Pay attention to how slushy the snow surface is, and think about how much snow could be moving with you on a steep slope.  Wet Loose avalanche activity will first occurr in the steepest terrain and begin near exposed rock or cliffs.  The snow may get slushy sooner in the day than we are used to because of the relatively warm night.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    2–3

    Deep Peristent Slab avalanches will remain in the forecast until the end of this warm period.  Lots of melting snow and the increased likelihood of Cornice Collapses will keep them relevant until the winter comes back.  For most of the month we have been referencing persistent weak layers that were formed in early January.  These layers are now burried more than 2 meters, which makes triggering an avalanche on these layers unlikely.  A Cornice Fall could easily trigger an avalanche on these layers.  Avoid big, steep and unsupported slopes, particularly when cornices loom overhead.

Avalanche Discussion

After last weekend's rain there is a lot of debris out there.  Today I observed Wet Loose avalanche debris across much of Tam Macarthur Rim as well as this large crown.  This one seems likely to have been a Cornice Fall / Wet Slab combo (maybe a little Deep Slab too?).  I also saw some debris low on the Villard Glacier of North Sister but visibility wasn't good enough to see if it was from Loose avalanches or Slab avalanches.

Regions covered