Avalanche Forecast
Regions: Cascades - East.
While wind slabs and storm slabs will continue to stabilize, recent cool weather may cause this process to take longer than usual. Keep an eye out for signs of recently wind transported snow.
Detailed Forecast
Sunny and mild weather on New Year ’s Day will continue to allow wind and storm slabs to gain strength. Expect colder temperatures and valley clouds to limit warming at lower elevations.
Look for areas of recently wind transported snow such as uneven snow surfaces, fresh cornices and snow drifts. Identify and avoid areas of wind loaded snow. Recent strong winds may have loaded slopes well below ridge crest. Pay attention to exposed terrain features even below tree line where wind slabs may have formed.
Wind slabs can be deceptively difficult to manage in the terrain. Take a moment and read our recent blog post by NWAC Pro Observer Jeremy Allyn on wind slabs.
While storm slabs are gaining strength, the amount of recent snow warrants caution before stepping into larger terrain.
Sunshine on Monday may produce small loose wet avalanches on steep sunny slopes especially near rock outcrops. Pay attention to new roller balls as these are a sign that loose wet avalanches could occur.
Despite recent snow, early season conditions still exist. Pay particular attention to open creeks that have not filled in for the season.
Snowpack Discussion
Happy New Year from your friends at the Northwest Avalanche Center.
Cool weather east of the Cascades has slowed the stabilization of wind and storm slabs formed during the recent active weather pattern.
Winds over the past several days formed firm reactive wind slabs on a variety of aspects.
Storm totals from across the area show 1-1.5 feet of snow feel during the series of storms ending Saturday. Layers within the storms snow have been reported from around the area, but trends continue to show these layers slowly gaining strength.
Snow depth decreases substantially the further east of the Cascade crest one travels. In many areas below treeline, there is not enough snow to present an avalanche danger.Â
Observations
North
North Cascade Mountain Guides were in the Washington Pass area both Friday and Saturday. By Saturday, cooling and settlement allowed for a favorable stability trend. The sensitive storm slab layers and avalanches seen Friday were gaining strength and becoming less likely to trigger.
Central
Mission Ridge Pro Patrol reported very sensitive wind slabs observed around the area Saturday. A natural avalanche cycle was observed from Friday night. Avalanche control work within the ski area Saturday produces 1-4 ft wind slab avalanches.
On Friday, a public skier triggered a 16-18†wind slab in closed terrain on a NE aspect at approximately 6000’. The skier was not caught nor injured.
South
No recent observations
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: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
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: All elevations.
Likelihood: Possible
Expected Size: 1 - 1