Avalanche Forecast
Regions: Olympics.
The strong storm Saturday should have created widespread new storm layers and new unstable wind slab on lee slopes near ridges by Sunday with further snowfall and winds expected during the day Sunday. Travel conservatively by staying off or below steeper slopes and avoid wind loaded north and east facing terrain.
Detailed Forecast
Snow showers will continue Sunday with moderate ridge top winds. Temperatures should remain cool.
Recent storm and wind slabs may continue to build and storm layers from Saturday and Saturday night will not have settled or stabilized by Sunday.Â
Storm slabs should remain sensitive and likely to trigger. North to east facing lee slopes will continue to be loaded throughout the day as well. Â
Dangerous avalanche conditions are expected near and above treeline requiring conservative decision-making and cautious routefinding.
Be aware of early season hazards below treeline. The heavy rains from last week have left many creeks open at lower elevations.Â
Snowpack Discussion
After a wet week that culminated with heavy rain Monday and Tuesday, melting the Waterhole snowdepth (5000 ft) down to around 18Â inches, winter has returned to lower snow levels and new snow. The NPS ranger at Hurricane Ridge reported a snowdepth of 34 inches Friday morning with 14 new inches received since Tuesday. Stormy conditions early Saturday curtailed an observation.Â
Avalanche and Snowpack Observations
NWAC pro-observer, Matt Schonwald was at Hurricane Ridge Friday, collecting the first snowpack observations in the Olympic zone for NWAC this season, welcome Matt! The snowdepth averaged around 1 meter (over 3 ft) with slightly more snow in less wind affected areas. The most recent snow has bonded well to the old surface and there were no significant storm snow instabilities. However, there were signs of significant wind loading onto open lee NE slopes, mainly applicable in the near and above treeline elevation bands.  Below treeline should still contain ample terrain anchors, but above 4000'-4500' there is enough snow to allow avalanches in specific areas.  No observations were received Saturday as a result of stormy conditions.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, North West.
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: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 1