Lawinenlagebericht

Elkhorns

Wallowa Avalanche Center
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Lawinengefahr

Sun
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Veraltet — dieser Lagebericht ist 5 months ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

The onset of cooler temperatures and an increase in cloud cover will decrease the likelihood of wet avalanches today.    We have just experienced 5 days of above-freezing temperatures in the mountains, and the upper snowpack has become saturated with meltwater.    Monitor the thickness and supportability of surface crusts and avoid steep terrain if you encounter wet, sloppy snow that is more than ankle-deep.  

This forecast is sponsored by Outlaw Motorsports in Enterprise, OR

Lawinenprobleme

  • Wet Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1.5–2.5

    The most recent freezing temperatures were recorded on the evening of March 16th.    This destabilized the upper snowpack as meltwater moved through the snowpack.   When this water pools at a crust or a weak layer, it can create a wet slab avalanche.   With all of the crusts and weak layers that exist in our snowpack, we have the structure to potentially see large or very large wet slab avalanches.  Consider this cooling trend a step in the right direction, but be patient as the upper snowpack may still need some time to refreeze.  Today, get curious about the thickness of the refrozen surface and how wet the snow beneath this crust may be.  

    Wet slab avalanches are notoriously destructive and difficult to forecast. While the chance of triggering such an avalanche may be low, the consequence would likely be catastrophic. Be particularly cautious on sun-affected slopes or very steep slopes with rock outcroppings.  If you see roller-balls, signs of recent avalanches, or find yourself sinking into wet, unconsolidated snow, move to lower-angle terrain until temperatures drop and the snowpack can stabilize.

     

Avalanche Discussion

Those who have been tracking the conditions along with us may be wondering, what happened to the persistent slab problem? Warming trends over the past week have almost eliminated the Valentine's Day Buried Surface Hoar layer, which was one of the persistent weak layers that we were tracking. The deeper persistent layers, the January Facets (down 2-4 feet deep), are still around, but with five consecutive days of unseasonably high temperatures, the biggest concern is now water pooling on these crust/facet layers and causing the now wet and consolidated slab above it to release.   Yesterday, many valley locations saw temperatures into the 70's, and the La Grande airport recorded a high temperature of 81° yesterday afternoon.   

Wet snow avalanches will slowly stabilize today as we see cooler temperatures filter back into the region, but today will be a transition day for the snowpack.  Wet snow avalanches come in a couple of different flavors: 

Wet Slab avalanches release as a cohesive slab of snow, and are notoriously destructive and difficult to forecast.  Although the likelihood of triggering such an avalanche may be decreasing, the consequences could still be catastrophic. Be particularly cautious on sun-affected slopes, and if you see roller-balls, signs of recent avalanches, or find yourself sinking into wet, unconsolidated snow, move to lower-angle terrain.

Lingering wet-loose avalanches could be found today in wind-protected, steep, and rocky terrain.  Avoid travelling on or below very steep, rocky terrain where wet-loose avalanches are most likely.  Wet loose avalanches would be smaller than wet slab avalanches, but can carry consequences as they could push you over exposed terrain or into a terrain trap.  

Large cornices along exposed ridgelines have become very weak during the latest warmup.  Give corniced ridgelines a wide berth, and minimize your exposure time if you must travel underneath overhanging cornices.  

Let's paint this picture together.  Let us know what you are seeing out there through an observation.  It doesn't need to be complex or technical- just a few pictures and a description of what you encountered is super helpful to forecasters.  

Beacon Parks: Thank you to everyone who helped establish the beacon training park at Anthony Lakes (across from the ski lift on Mud Lake) and near the warming shelter at Salt Creek Summit snopark outside of Joseph, OR. This is a valuable free resource that everyone should use to practice their companion rescue skills. 

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