Avalanche Forecast
Regions: Stevens Pass.
A continued mix of winter like and spring conditions should continue early Sunday with increasing wet snow conditions by Sunday afternoon.
Detailed Forecast
Updated Sun AM to increase avalanche danger, especially storm slab near and above treeline and wet loose avalanche concerns lower in elevation.  3"-10" of new snow fell Saturday and Saturday night generally above 5000 feet along the west slopes.  Also, watch for and generally avoid weakened cornices along ridges.Â
A front with increasing clouds and moisture will move across the region Saturday night, then east of the area Sunday. This is expected to cause increased winds and increasing rain and snow with slightly rising snow levels late Saturday and Saturday night.
This system should build some new shallow wind and storm slab at higher terrain and increase surface wet snow conditions below tree line. Â Â
Watch for natural avalanches, pinwheels and surface wet snow deeper than a few inches on any solar slope Sunday. Â Watch for evidence of wind transported snow in the higher terrain.
Remember to watch for cornices if you venture onto the ridges and avoid slopes below cornices. Cornice failures are often seen during the transition to spring weather. Cornices have grown large recently and may break back further from the edge than expected.Â
Snowpack Discussion
An upper low moved southward off the coast early last week and largely missed the Northwest. But locally strong east winds were seen mainly near and above treeline and mainly in the South Cascades. NWAC observers Tom Curtis on Mt Adams Tuesday and Dallas Glass on Mt. Rainier on Wednesday reported redistributed snow and cross loaded slopes. Dallas reported 20-40 cm of wind slab in the 6400-7500 foot range with natural avalanches on a variety of aspects. Older wind slab will not be listed as a concern due to anticipated new wind slab development Saturday night.
A fair weather period with little avalanche activity was seen midweek.
A front crossed the Northwest on Thursday, causing moderately increasing winds, varied amounts of new snow and slightly lower snow levels. New snow amounts varied from 8-15 inches in the Mt Baker areas, including the Grouse Mtn area. The areas around Paradise on Mt Rainier received 8-10 inches with most other west slope Cascade areas 4 inches or less.
Following the front Thursday, the Mt Baker and Alpental patrol reported active results from ski and explosive control work.Â
By Saturday, the storm layers had settled significantly with slope testing by ski and explosives in both the Baker and Alpental areas producing limited to no results.  Some shallow wet snow conditions were reported below tree line at Alpental by Saturday afternoon.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: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 1
Loose Wet
Release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. They generally move slowly, but can contain enough mass to cause significant damage to trees, cars or buildings. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.
Travel when the snow surface is colder and stronger. Plan your trips to avoid crossing on or under very steep slopes in the afternoon. Move to colder, shadier slopes once the snow surface turns slushly. Avoid steep, sunlit slopes above terrain traps, cliffs areas and long sustained steep pitches.
Several loose wet avalanches, and lots of pinwheels and roller balls.
Loose wet avalanches occur where water is running through the snowpack, and release at or below the trigger point. Avoid terrain traps such as cliffs, gullies, or tree wells. Exit avalanche terrain when you see pinwheels, roller balls, a slushy surface, or during rain-on-snow events.
Aspects: South East, South, South West.
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: Possible
Expected Size: 1 - 1