Avalanche Forecast
Regions: Olympics.
A cooling trend should stabilize a wet upper snowpack, while light snow showers and sustained westerly wind will build shallow wind slab concerns throughout the day. Observe signs of wind transport, such as scoured ridges, pillowy snow surfaces, or fresh cornices and avoid nearby steep or unsupported lee slopes.
Discussion
A major storm was a little bit too warm for snow at Hurricane Ridge. Snow levels rose right as precipitation arrived on Tuesday, so Hurricane Ridge picked up 0.62†of rain during the day, which was “blowing sideways†and mixing with sleet at times. While the temperature hovered just above freezing, we think that even the above treeline elevations (up to 7000 ft) likely picked up rain on Tuesday. Snow levels should begin dropping during the late evening hours and we expect post-frontal snow shower activity to bring 4-8†of new snow to Hurricane Ridge from late Tuesday night through Wednesday, with less as you go down the hill.Â
We think this rain has moistened the upper snowpack and largely limited pre-existing avalanche concerns.
Travel concerns on New Year’s Day include refreezing crust surfaces and shallow snowpack with open creeks and partially submerged obstacles below treeline.
Forecast Schedule
For the 2019-20 winter season, avalanche danger ratings will be issued for the Olympics every Friday through Sunday and during mid-week holidays. During the week, No Rating will be issued but forecasts will include expected conditions and relevant travel advice. If you are out in the Olympics, share your backcountry observations with us and the greater community.
Snowpack Discussion
New Regional Synopsis coming soon. We update the Regional Synopsis every Thursday at 6 pm.
Avalanche Problems
Wind Slabs
Small wind slabs developing late Tuesday night through Wednesday should introduce the first avalanche concerns of the new decade at Hurricane Ridge. Although we expect the new snow to bond well to the wet underlying snow, evaluate this interface in case the snow bonds poorly to a refrozen crust. Look for fresh cornices or chalky textured slopes as visual clues to avoid wind-loaded terrain features steeper than 35 degrees.
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: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 1