Avalanche forecast

Central Cascades

Central Oregon Avalanche Center
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Avalanche danger

Wed
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

There were no reports of avalanches in the Cascades on Monday.  It remains possible to trigger an avalanche on the Dec. 8th surface hoar in very isolated locations.  Think of this as a low likelihood, but high consequence event.  Additionally shallow, stubborn Wind Slabs exist on East slopes at and above treeline.

Avalanche problems

  • Persistent Slabs

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

    It is possible to trigger a large avalanche on the Dec. 8th burried surface hoar.  These avalanches are likely to be very isolated.  On the majority of slopes observers have been finding this layer to be largely unreactive.  However, there are isolated slopes where the burried surface hoar remains intact and potentially dangerous.  For example, today I observed 1 cm standing surface hoar burried 40 cm. on a NE slope at 6520 ft. in a glade near Mckenzie Pass (see picture of post ECT).

    When choosing ski terrain, keep in mind where surface hoar likes to form best.  It particularly likes glades that are Cold, Clear and Calm.  It would have been preserved on the surface best on slopes that see minimal sun and wind.  Slopes that see minimal / no skier traffic can also contribute to the problem.

    This is a good time to dig.  Your "go to" tools should be the compression test, as well as observing obvious intact surface hoar in your profile.

    (12/12/2022)

    ECTP 11

    NE Glade at 6520 near Mckenzie Pass

    Photo: Gabriel Coler

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    Weather stations and field observations on Monday showed wind speeds along the Cascade Crest reaching just into Moderate from the North and Northwest.  There was evidence of previous blowing snow.  All this despite the forecast for Light winds proves that it is a rare day when it's calm high in the Cascades.  On Monday Wind Slabs felt shallow and stubborn on East aspects.  They will likely continue to stabilize in to Tuesday.

    Terrain to watch in particular are wind loaded slopes that may also have burried surface hoar.  Even a shallow wind slab could step down and increase in size.  I'm picturing steep East slopes at treeline.

    (12/12/2022)

    Evidence of blowing snow near treeline

    Photo: Gabriel Coler

Avalanche Discussion

Our snow height averages 150 cm.  Widespread surface hoar from last week was burried on Dec. 8th.  This layer has proved to be mostly unreactive.  There are isolated spots out there where we are getting sudden collapses in our compression tests.  It is burried 40-50 cm deep.  Our mid and lower pack aren't presenting any concerns.

Regions covered