Avalanche forecast

Central Cascades

Central Oregon Avalanche Center
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Avalanche danger

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

Triggering avalanches in wind drifted snow will be likely on Thursday on north, east, and south facing slopes near and above treeline. Multiple weak layers in the old snow at mid and upper elevations on northern and east facing slopes are still something to keep in mind and investigate, although avalanches on these layers are unlikely. When you have uncertainty in the snowpack consider moving to slopes less than 30 degrees steep. 

Avalanche problems

  • Wind Slabs

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

    There will be quite a lot of variability with this problem on Thursday. Most wind slab avalanches will be on the small (D1) side of the spectrum, however isolated features could produce large avalanches as more snow stacks up throughout the day and the westerly wind moves snow around. Also I expect most wind slabs to be building on NE, E, and SE facing slopes, but watch for the crossloaded features on north and south facing terrain. The key with this problem will be to monitor how deep the wind slabs become. As wind slabs build to 10" or more, resulting avalanches will pack more punch. Watch for blowing snow, and where that snow is moving to as an indicator of which slopes are actively becoming wind loaded. Remember, wind can pile up snow many times deeper than the snow that fell out of they sky. 

  • Persistent Slabs

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

    There are two persistent weak layers observers have been tracking in the snowpack. A buried surface hoar layer is down 12-16". A layer of faceted snow is down around 16-20".  We have not seen any avalanche activity on these layers. The new incoming snow is not putting a huge load on these weak layers. The place where likelihood of triggering a persistent slab avalanche could creep up is where large deposits of wind slab are accumulating. The wind slab and persistent slab problem are overlapping in distribution. Take this into account before committing to slopes. Also before committing to avalanche terrain in the problem distribution, consider digging into the snowpack and checking out the condition of these weak layers. 

Avalanche Discussion

Avalanches likely and moderate danger? The moderate danger reflects that most of the wind slab avalanches on lee terrain features will be small. Natural avalanches are unlikely but not out of the question.

Small loose snow avalanches or small storm slab avalanches could make an appearance but not large enough to really consider a problem. As always, remember small avalanches can lead to consequences in steep terrain or above terrain traps. 

 

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