Avalanche forecast

Central Cascades

Central Oregon Avalanche Center
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Avalanche danger

Sat
Alpine
4 · High
Treeline
4 · High
Below
3 · Considerable
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Highlights

Triggering large avalanches in wind deposited snow will be very likely near and above treeline. Triggering avalanches in the new storm snow will be likely anywhere the wind has not stripped the snow away. This will be a day to make conservative terrain choices. The safe bet is to choose slopes less than 30 degrees steep and avoid being under steep slopes. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    2–3

    Wind slabs will not be everywhere, but they could be anywhere. The wind will be shifting from out of the south and west with wind speeds into the 30 mph range. There will be a lot of blowing snow over the next 24 hours. Some avalanches may be small, but with the current conditions wind slabs have the potential to be much larger than what we normally see in central Oregon. 

    Wind slabs may show up in unusal places. Watch for wind slabs building in clearings and areas with sparse trees even below treeline. Remember burned areas and slopes with dead trees can experience a big wind affect and get a lot of wind deposited snow. 

    Naturally triggered wind slabs will also be likely.....keep that in mind if you find yourself travelling below wind loaded slopes.

    Use visual clues to identify where wind slabs have formed and are building below ridge tops, peaks, and around features that catch blowing snow from cross slope winds. Monitor the depth of wind deposited snow. As the new snow stacks up and wind slabs become deeper, resulting avalanches can become larger. Wind slabs typically form below ridgetops, high points, and around any features that catch wind blown snow. 

     

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2.5

    By Friday afternoon we could see around 30+ inches of recent storm snow stacking up. Triggering a storm slab will be more likely in steep, convex, rolling terrain but can occur anywhere the slope is steep enough for snow to move. 

    If the snow at the surface is not exhibiting slab properties (i.e. cohesion) storm slabs can still be present. The sheer volume of new snow can release on storm weak layers.

    Storm slab avalanches are soft slabs......trees won't hold them in place. Evaluate the storm slab problem by utilizing small safe slopes. Looking for shooting cracks and/or slabs releasing on small test slopes.

  • Loose Dry

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

    It is unusual to post dry loose and storm slab problems at the same time, but this is one of those days. With cold overnight temperatures, the snow will be lacking cohesion near the surface. Dry loose avalanches in steep terrain will have the chance to entrain more snow and run farther that usual.  Be especially cautious in steep and committing terrain, above terrain traps, and constrictions or places where the terrain can act like a funnel. 

Avalanche Discussion

Cracking in the surface slab and recently triggered avalanches are obvious signs of unstable snow. Even if you don't see those signs, do not assume the problem is not present.

If you do venture into avalanche terrain, make very carefull terrain assessments. Triggering a small or large avalanche above terrain traps such as cliffs, rocks, trees, gully features can lead to a worse outcome. 

Cornices are still out there and growing. Fresh cornices can be fragile,  break easily, and can trigger slides on the slope below. Be cautious when approaching ridge tops where cornices may be lurking over lee slopes. Stepping out onto a cornice could result in a break and an air drop onto the slope below. 

 

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