Avalanche Forecast
Regions: Stevens Pass.
Expect increasing avalanche danger with elevation on Saturday... with the likelihood of wet loose avalanches decreasing and new storm and wind slab avalanches increasing.
Detailed Forecast
The next system in our active weather pattern should bring on average another inch of water to the west slopes Saturday during the daylight hours as a weather system lifts northward.   Â
Lowering snow levels and light to moderate precipitation Saturday should build new storm and wind slab above about 5000 feet or so. Storm related avalanche concerns will increase with elevation Saturday. Despite the cooling trend, expect the snow surface below any new snow near and even above treeline to be wet, and skier triggered loose wet avalanches will still be possible during this transition.  Â
The below treeline snowpack should continue to drain and be capable of handling additional rain without a significant increase in avalanche danger. Small wet loose avalanches will still be possible on steeper slopes below treeline.Â
Remember, due to the unseasonably low snowpack especially at lower elevations, numerous terrain hazards such as open creeks, partially covered rocks and vegetation are widespread. Â
Snowpack Discussion
Mild weather the last week of January led to significant snowpack consolidation. The snow level oscillated around 4000 feet earlier this week... with a few inches of new snow accumulating generally near and above treeline, the most at Mt. Baker above 4500 feet. The atmospheric river faucet turned on Thursday and Friday, with most west slope locations picking up several inches of rain due to the mild snow levels. As of 5 pm Friday, Mt. Baker has picked up an amazingly wet 9 inches of mostly rain over the last 48 hours.Â
Observer Tom C. was in the Rainy Pass area near Stevens on Thursday. With a transition to rain in the late morning, Tom observed natural small wet loose and wet slabs releasing on steeper slopes below treeline involving the most recent snow over a rain crust. Wet loose involving the most recent snow were also ski cut by professional patrollers at Crystal and Alpental Thursday.  By Friday, no significant wet loose slides were observed below treeline by professional patrols across the west slopes.  Dallas Glass in the Skyline area of Stevens on Friday found above 5000 feet (approaching near treeline), there was enough recent storm snow for more significant natural or skier triggered wet snow avalanches and observed pinwheeling of the surface snow.   Â
Small wet loose, Rainy Creek. 2-5-15 by T. Curtis
The mid and lower snowpack west of the crest should consist 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, Treeline.
Likelihood: Possible
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.
Elevations: Treeline, Below Treeline.
Likelihood: Possible
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, North West.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 1