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RegisterFeb 22nd, 2018–Feb 23rd, 2018
Olympics.
New shallow and wind slabs will form in the Olympics on Friday. Identify and avoid areas where the wind is actively depositing snow. Persistent slabs are still present in the Olympics. Avoid steep open slopes greater than 35 degrees where you are most likely to trigger this very difficult to manage avalanche problem.
New snow and moderate winds will cause the avalanche danger to increase slightly Friday, as slabs grow larger and become easier to trigger.
Fresh shallow wind slabs will form on lee slopes as winds increase. You will most likely trigger these avalanches on steep slopes below blowing snow, plumes, and fresh cornices. Identify and avoid steep terrain where winds are actively loading new snow.
In many locations a persistent weak layer exists within the snowpack. Around 2 feet of settled snow sits on top of weak sugary facets buried on 2/13. At least 2 avalanches have been triggered by backcountry travelers on this layer during the past week in the Olympics. Persistent slabs can be difficult to manage. They do not heal as quickly as other avalanche problems and can remain active for weeks at a time. Observations on where these weak layers are present and how easy they are to trigger is hard to obtain. Give youself a wide safety buffer to handle the uncertainty around persistent slabs. Avoid slopes greater than 35 degrees where this problematic avalanche concern is thought to exist.
Excellent travel conditions can still be found in lower angle sheltered terrain not exposed to steep overhead slopes.
Two feet of settled snow exist around the Hurricane Ridge area over the 2/13 weak layer in sheltered areas. In exposed terrain, winds have redistributed snow near and above treeline. Wind deposited snow can be found on a variety of aspects along ridgelines.
Weak old snow (facets) can be found above the most recent crust layer. In most locations this is 1.5-2.5 feet below the snow surface. Observations continue to indicate this layer is reactive and capable of producing large avalanches. This layer has been reported on all but due South aspects.
There are no other significant layers of concern in the mid and lower snowpack.
Observations
On Friday Matt Schonwald and NPS rangers observed 20-30 inches of generally right-side-up surface snow over weaker snow (facets). Snowpack tests indicated the weak facet layer could still fail and produce avalanches. Northeast winds during the day Friday redistributed snow onto SW-W-NW aspects.