Avalanche Forecast
Regions: Stevens Pass.
Shallow storm slabs are possible above treeline Wednesday especially on lee easterly aspects.
Detailed Forecast
A frontal system should bring light to occasionally moderate rain and snow to the west slopes Tuesday night and Wednesday. New snow above 5500-6500 ft may form shallow storm slabs above treeline, especially on lee easterly aspects, but new slabs should be shallow enough to keep the avalanche danger low. The snowpack should be well drained and setup to handle rain at lower elevations.
Due to the low snowpack, especially below treeline, watch for terrain hazards such as open creeks, partially covered rocks and vegetation. Many areas below treeline do not have enough snow (new or existing) to pose an avalanche hazard.
Snowpack Discussion
As the last snowfall in the Cascades is becoming a fading memory, occurring near the end of February when about 8-13 inches fell near and above treeline west of the crest from Snoqualmie Pass to Mt Rainier with less elsewhere along the west slopes. This was followed by moderate northeast winds in the Cascades forming locally touchy windslab in the Crystal and Mt. Rainier backcountry.Â
Sunny and gradually warmer weather has been seen the first third of March helping to stabilize local wind slab from the end of February and further consolidate the snowpack. Recent reports throughout the Cascades generally indicate hard or firm melt-freeze crusts or stable old snow still preserved on non-solar aspects at elevation. Â
There was almost no snowfall in January and February and none so far in March. The snowpack at lower elevations is meager and way below normal. There have not been any reports of significant avalanches for a long time.Â
The mid and lower snowpack west of the crest snow consists of layers of stable consolidated rounded grains or melt forms and crusts from multiple warm periods this winter.
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: Alpine.
Likelihood: Possible
Expected Size: 1 - 1