Avalanche forecast

Central Cascades

Central Oregon Avalanche Center
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Avalanche danger

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

On Monday it will be possible to trigger a Wind Slab avalanche on north and east facing slopes that have wind deposited snow.  Avoid committing to steep wind loaded terrain until you feel confident in your snowpack assesment.  Observations continue to trickle in that mention weak layers deep in our snowpack.  While triggering a Deep Persistent Slab remains unlikely, the consequences would be catastrophic.  Avoid slopes that are big and steep, shallow, and unsupported.

Avalanche problems

  • Wind Slabs

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

    Wind Slab avalanches are nearly always a possibility when we have new snow in the forecast, because it is rare for us to have calm or even light winds when it is snowing.  On Monday the danger from Wind Slabs will increase throughout the day as more snow falls.  Remember that wind deposited snow can be 3-5 times as deep as the snow that has fallen from the sky.  Often on these days, avoiding steep and convex slopes below ridgelines is the easiest strategy (I tend to like easy startegies).  If you shoose to venture onto these slopes, first assess the Wind Slab avalanche problem on slopes less than 30 degrees or small enough not to be dangerous.

  • Deep Persistent Slabs

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

    The last very large avalanches were observed a week ago as the skies cleared after our big storm.  Since then, there was one public observation from Broken Top that included mention of collapses.  Our forecast team is in constant discussion about when we can leave this problem in the rearview, and we're not there yet.  The layers in question include burried surface hoar and near crust facets that are now burried 160-200 cm deep.  It is unlikely that a rider's weight would penetrate to collapse a weak layer that deep, but these avalanches can be triggered at shallow trigger points and by other avalanches or cornice failures.  Avoid large, steep slopes that you expect could be shallow or rocky.

Avalanche Discussion

Since any instabilities on Monday will predominently exist in the new snow, use hand shears and small test slopes to determine if the new snow is cohesive and if a weak layer exists.

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