Avalanche Forecast
Regions: Olympics.
New snow and wind will create dangerous avalanche conditions Saturday. You can trigger an avalanche on any steep wind loaded slope. Moderate NE winds will load unusual aspects and build wind slabs on open slopes below treeline as well as higher terrain. In wind sheltered areas, loose dry avalanches can run fast and far, don't let them catch you off guard.
Discussion
Snow and Avalanche Discussion
It's been a quiet few weeks avalanche-wise in the Hurricane Ridge area. That began to change on Friday as 7" of low density snow fell quickly during the day with little wind. NPS rangers reported natural and skier triggered loose dry avalanches releasing on steep northerly aspects as the snow piled up.Â
Avalanche conditions are expected to worsen Friday night through Saturday as additional snow and wind impact the Hurricane Ridge area. Snow, blowing snow, and temperatures in the single digits will hamper safe travel and group communication.Â
NWAC professionals in the Hurricane Ridge area on Thursday found about 5-7 inches of low density snow above the most recent thin crust. The snow surface was weaker (more faceted) on north through east aspects near and above treeline in the terrain they traveled. Avalanches are more likely to fail on these weaker, older snow interfaces.
Loose dry avalanches will continue to be a concern in very steep terrain that isn't wind affected. Keep this in mind around terrain traps; you don't want a small but fast moving avalanche to take you on an unexpecting ride into trees or over a cliff. Â
Forecast schedule
For the 2018-19 winter season, avalanche hazard ratings will be issued for the Olympics Friday through Sunday and during holidays. We will resume issuing ratings when access is once again available following the recent government shutdown.
General snowpack and weather summaries will be available on days that the Hurricane Ridge road is closed.
Snowpack Discussion
Regional Synopsis coming soon.Â
Avalanche Problems
Wind Slabs
Avoid steep wind loaded slopes in all elevation bands Saturday. New wind or storm slabs may be especially touchy on north or east aspects where they build over weaker, older snow surfaces. In addition, Northeast winds are expected to build wind slabs on unusual aspects. With all of this in mind, it will be difficult to manage avalanche conditions Saturday, so stay safe and choose simpler terrain.
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: All elevations.
Likelihood: Likely
Expected Size: 1 - 1