Avalanche Forecast
Regions: Cascades - North East.
Due to a shallow snowpack at low elevations... the greatest avalanche danger should be present in the near and above treeline zones within the new storm snow. Storm conditions should develop Saturday; don't be fooled by low snow cover at the trailhead and be aware of what terrain you are connected to above.
Detailed Forecast
A strong plume of moisture headed toward the Pacific Northwest should bring copious amounts of precipitation and wind to the mountains this weekend. Â
On Saturday, snow levels should start low and rise throughout the day as precipitation intensity increases during the daylight hours. The biggest avalanche concern for Saturday will be direct-action wind and storm slab avalanches.  Rising temperatures should cause an upside down snowfall... and at lower and mid elevations a changeover to rain will load snowfall received earlier in the day. Heavy periods of snowfall will lead to storm snow instabilities. Also, increasing SW winds should scour exposed ridgelines and quickly load north through southeast aspects.  Â
New snowfall received Saturday and Saturday night will test recently buried weak layers. Warmer air should mix even into the northeast Cascades by Sunday morning. Â Check the mountain weather forecast for details.Â
This is not the weekend to be exploring new areas. If you do venture out Saturday, know your route and avoid areas where you are connected to slopes with higher avalanche potential above.Â
Snowpack Discussion
The northeast Cascades is the one forecast area where the snowpack is at least a meter deep or more in the tree-line elevation band and has already experienced several natural avalanche cycles. Â
Pro-observer Jeff Ward and the North Cascade Mountain Guides have been tracking several layers of concern... either buried surface hoar or facet/crust combos formed earlier this month. These layers are likely to be found in the upper 35 cm of the snowpack between 5500-6500 feet in the Washington Pass area.  While these layers have been reactive in snowpack tests... they have not been observed in any recent avalanche activity and need more load to stress and test these layers.Â
We do not have much snowpack information about our Cascade East - Central zone.  Snowpack depth away from the crest (Blewett Pass, Mission Ridge) is marginal for avalanche activity even at higher elevations. The avalanche rating for this area corresponds best to areas near the Cascade crest where a deeper snowpack exists. Â
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.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 1