Avalanche Forecast
Regions: Olympics.
Storm concerns should decrease through the day Friday, but watch for sensitive new storm and wind slab, especially on lee N through SE slopes near and above treeline. Careful route-finding and snow evaluation will be essential.
Detailed Forecast
Showers should diminish overnight through Friday morning.  A low pressure system diving south should largely miss the Olympics Friday with partly sunny skies expected in the afternoon.
Watch for sensitive new storm and wind slab, especially on lee N through SE slopes near and above treeline. Although we can make an educated forecast about the snowpack stability in the Olympics, carefully evaluate the snow and terrain for yourself.  Â
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Snowpack Discussion
After a wet week that culminated with heavy rain Monday and Tuesday knocking the Waterhole snowdepth (5000 ft) down to around 18 inches, we have returned to snow levels and a snowdepth of around two feet as of this morning. Several more inches have likely fallen through the day with predominately SW winds at ridgetop.Â
Avalanche and Snowpack Observations
Given the warm, wet weather over the Olympics earlier in the week, it is likely that the upper snowpack has consolidated and drained. We will likely have built new, shallow and potentially unstable storm snow layers within the last 24 hours, especially on leeward slopes near and above treeline. Below treeline should still contain ample terrain anchors, but above 4000'-4500' there is likely enough snow to allow small avalanches in specific areas.Â
While we have not had a specific snowpack observation from Hurricane Ridge thus far this season, new NWAC observer Matt Schonwald will be taking observations from Hurricane Ridge beginning this weekend!Â
Avalanche Problems
Wind Slabs
Release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Wind Slabs form in specific areas, and are confined to lee and cross-loaded terrain features. They can be avoided by sticking to sheltered or wind-scoured areas..
Wind Slab avalanche. Winds blew from left to right. The area above the ridge has been scoured, and the snow drifted into a wind slab on the slope below.
Wind slabs can take up to a week to stabilize. They are confined to lee and cross-loaded terrain features and can be avoided by sticking to sheltered or wind scoured areas.
Aspects: North, North East, East, South East.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 1
Storm Slabs
Release of a soft cohesive layer (a slab) of new snow that breaks within the storm snow or on the old snow surface. Storm-slab problems typically last between a few hours and few days. Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
You can reduce your risk from Storm Slabs by waiting a day or two after a storm before venturing into steep terrain. Storm slabs are most dangerous on slopes with terrain traps, such as timber, gullies, over cliffs, or terrain features that make it difficult for a rider to escape off the side.
Storm slabs usually stabilize within a few days, and release at or below the trigger point. They exist throughout the terrain, and can be avoided by waiting for the storm snow to stabilize.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1 - 1