Avalanche Forecast
Regions: Olympics.
Dangerous avalanche conditions are expected by Thursday afternoon. Reign in your objectives later in the day as snowfall and winds increase by avoiding steep and wind loaded slopes, watching for sensitive storm layers. Recent and newly wind loaded slopes in the near and above treeline zone should be found on a variety of aspects Thursday.
Detailed Forecast
A frontal system on Thursday should bring light to moderate snowfall in the Olympics along with a gradual warming trend. Â
Avalanche problems will revolve around storm and wind slab. New and recent snow will be deposited on lee NW through NE aspects, although initially be wary of lingering wind slab on E-SE slopes from transport earlier in the week. Most avalanches should stay within the new storm snow, but a few may step down to older storm layers or crusts in isolated locations.  Â
As snowfall and winds increase, avoid steeper slopes and watch for increasingly sensitive storm layers. Rain should also activate storm slabs below and near treeline by Thursday afternoon. Generally avoid wind loaded terrain in the near and above treeline zone with new snow being transported to a variety of aspects.
The storm related avalanche danger will increase further Thursday night into Friday morning. Â
Terrain anchors are still causing significant anchoring at the lowest elevations. Use caution near creeks which are still open in some areas.
Snowpack Discussion
An atmospheric river around Dec 9th pushed heavy rain above treeline in the Olympics. This caused consolidation and stabilizing of the older part of the Olympics snowpack. An active and cool weather pattern over the last week has produced about 2 to 3 plus feet of new snowfall near Hurricane Ridge that now sits over the 12/9 rain crust.
Last Sunday a NPS Ranger at Hurricane Ridge reported a storm slab release below the Sunrise Ridge likely on an east facing slope near Hurricane. The slide was likely triggered but this was not confirmed.  The avalanche crown was estimated at 2-3 feet and released about 150 wide and ran about 100 feet vertical - big enough to get into serious trouble.
Cool weather with light new snowfall has been seen Monday through Wednesday. This will have allowed further consolidation and stabilizing of recent storm snow instabilities.
Avalanche Problems
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: Likely
Expected Size: 1 - 1
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, North West.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 1