Avalanche forecast

Central Cascades

Central Oregon Avalanche Center
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Avalanche danger

Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

A large snowstorm begins tonight/Monday morning and will likely lead to our largest avalanche cycle of the season.  The danger will rise throughout the day in proportion to the amount of snow that has fallen.  As the snow piles up stick to smaller, less consequential terrain.

Avalanche problems

  • Storm Slabs

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

    With so much new snow in the forecast, Storm Slab avalanches will be possible in any terrain that is sheltered from the wind.  Storm Slabs will be particularly likely on North facing slopes below treeline where the old surface snow is most likely to be weak and faceted.  Keep this in mind and don't automatically apply the observations that you gather on other aspects.  Targeted hand shears might be your best tool to observe bonding of the new snow across a wide range of terrain.

  • Wind Slabs

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

    A lot of new snow will be falling, accompanied by South West winds varying from Extreme to Moderate.  Tomorrow is a good day to avoid wind affected terrain; it will be dangerous, and it wouldn't likely be enjoyable riding anyway.

  • Loose Dry

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

    Storm Slabs will be the primary concern in terrain below treeline, but with temperatures cooling throughout the day we may also see Dry Loose avalanches.  Remember that these two problems are not always mutually exclusive.  With lots of snow in the forecast this is a good day to steer clear of terrain traps.

Avalanche Discussion

The Oregon Cascades will be receiving a lot of new snow on Monday.  Fluctuations in the temperature and high wind speeds will create instabilities in this new storm snow. 

In many locations this storm snow will be falling on Sunday's weak surface snow.  Cold temperatures at the close of last week drove near surface faceting that continues to exist on slopes that are sheltered from the sun and wind (North facing glades below treeline).  This weak snow may mean that Storm slabs are touchier and propogate farther than you might expect.  While your best snowpack tests will continue to be targeted hand shears, and test slopes, this is also a good time to do some digging and compression tests.

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