Avalanche Forecast
Issued: Dec 28th, 2013 10:00AM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
NWAC,
Northwest Avalanche Center
Summary
Detailed Forecast
Becoming mostly cloudy Sunday with a chance of a little light rain or snow along with some cooling. Any light precipitation that may fall Sunday should not change the overall mostly low avalanche danger. Above treeline some isolated pockets of wind slab may persist below ridges mainly on shaded high elevation northerly facing terrain.
Snowpack Discussion
Very little recent snow and an overall very shallow snowpack are limiting the avalanche potential on most terrain, at least in the Hurricane Ridge area of the Olympics. Recent weather has been a mix of dry warm and sunny weather with periodic weak frontal passages depositing light amounts of new snow and/or rain.
In the Hurricane Ridge area the only slopes with sufficient snow cover to create an avalanche potential are on steep shaded northerly facing slopes near or above treeline. In those areas, the snowpack mostly consists of firm surface or near surface crusts with possible shallow recent wind deposits. Slopes exposed to either wind or sun have little to no snow to just above treeline.
There has been no recent avalanche activity reported in the Olympics.
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.
Likelihood
Expected Size
Valid until: Dec 29th, 2013 10:00AM
