Avalanche forecast

Blues

Wallowa Avalanche Center
View on map

Avalanche danger

Fri
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
No rating
Open full map
Out of date — this forecast expired 2 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Cooling temperatures have helped our wet snow avalanche problem, but it still remains possible to trigger a wet loose avalanche if you find yourself in wet unconsolidated snow in steep terrain.   Worrisome persistent weak layers still exist in the upper 2 feet of the snowpack and it is possible to trigger a large and destructive avalanche on mid and upper-elevation shady aspects.  If you find yourself in wet snow up to the top of your boot, it's time to scoot.  Careful snowpack evaluation is warranted before committing to any avalanche terrain that may be harboring a persistent weak layer. 

This forecast is sponsored by  CB Construction, Inc. 

Avalanche problems

  • Loose Wet

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

    The last week of warm and sunny weather has melted snow in the upper snowpack and water has dripped through the snow until it has reached a crust buried in the upper 2 feet of the snowpack.  This has created unstable upper snowpack conditions during the heat of the day.   Many natural wet loose avalanches have been observed since last weekend.  These often occur on solar aspects near rocks or cliff bands.  Last night, temperatures dropped below freezing at some, but not all weather stations.  Until we see a solid freeze at night coupled with lowering daytime temperatures, the likelihood of triggering wet loose avalanches in terrain steeper than 35 degrees remains possible.  

    Cloudy skies can help slow the onset of natural wet loose avalanches as the amount of direct sun that warms the surface of the snow is reduced.  That being said, the upper snowpack has been affected by strong solar input and multiple days without freezing temperatures and will take some time to lock back up once temperatures start to drop.   Even a smaller wet loose avalanche has the potential to knock you off your feet and carry you over consequential terrain or push enough snow into a terrain trap to bury you.  

    In your travels in the mountains today, pay attention to how wet the snow is under your feet or machine.  Get curious and dig down a few feet and see how wet the surface snow is as well as how deep water has percolated in the snowpack.  If you step off your machine or boards and are sinking up to your boot tops in wet snow, it's time to head to terrain less than 30 degrees in steepness.  

    Wet Loose avalanches on an East aspect at 8,000' in the Western Wallowas.

    Photo: Wallowa Avalanche Center

  • Persistent Slabs

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

    As your search for soft snow leads you to shadier aspects, you need to have your wits about you. 

    Last week forecaster Michael Hatch traveled to Spout Springs and found a thin layer of buried surface hoar down 8" at the new/old snow interface on a north-facing slope near 5200' in elevation. Surface hoar is notorious for being a persistent and reactive weak layer when buried.  If you collapse this weak layer in a shallower area on the slope (say around rocky terrain or wind-scoured areas) or roll over a steep convexity, the propagating fracture could trigger a large and destructive avalanche.  Avoid potential trigger points and steep (>35 degrees) convex rollovers, especially near treeline and mid-slope. Surface hoar forms in more open and protected terrain with little sun, so you'll find in mostly on shady slopes NW-N-NE. There is a lot of spatial variability of this layer across the slope. It is hard to see in the snowpack as it is a very thin layer. When in doubt, do snowpack tests, and better yet, choose lower-angle terrain to recreate in. You can always choose to avoid avalanche terrain altogether, and at the very least, ride on aspects where this problem is less likely to exist. 

    To decrease your chances of getting mixed up in this sort of fight, a thorough snowpack analysis is suggested before committing to any slope greater than 30 degrees on Northeast through Northwest aspects near and above treeline.  When you have uncertainty around the presence of these persistent weak layers, choose simple terrain less than 30 degrees.  

    (3/13/2024) Photo: Wallowa Avalanche Center

Avalanche Discussion

The snowpack has undergone a big change in the last week in the way of very warm temperatures and freely moving water in the upper snowpack.  Colder temperatures and more snow are on the horizon, but we are not out of the woods!  Stay vigilant in your mountain travels and snowpack assessment.  Many of us have built a mental winter road map that suggests stabilizing deeper snowpack conditions by this point in the winter.  The weather and snowpack this season demand that we recalibrate that operational memory and accept the current conditions.  Make a conservative travel plan to avoid areas where you have a higher level of uncertainty of the presence of persistent weak layers.  Avoid wet sloppy snow conditions as this is where wet loose avalanches are more likely to occur. 

The recent warm spell has destabilized cornices to the point that they could break naturally or as you step or ride near them.  Check out Wallowa Alpine Huts guide Killian Sump's observation here that notes several natural cornice failures and a recent slab avalanche in the Southern Wallowas.  Give cornices a "wider than you think" buffer.  

If you are out and about in the Blues, submit an observation of what you are seeing here.  I'll be traveling there on Saturday and provide an update with what I am seeing.  

No danger rating has been issued for the lowest elevation band in the Blues (3000'-4000') due to the lack of snow in that zone. If we receive significant low elevation snow we will begin forecasting for that zone again.

Regions covered