Avalanche Forecast
Regions: Cascades - South West.
Winds slabs will be less likely, but remain the primary concern Sunday and should generally be found on non-traditional westerly aspects, especially below ridges. Careful route finding and attention to local loading patterns will be necessary to have a safe and enjoyable day in avalanche terrain.
Detailed Forecast
Mostly sunny Sunday with increasing high clouds late, remaining cool with light winds. This should allow for further settlement of any recently formed wind slabs. Winds slabs will remain the primary concern Sunday, so pay attention to the recent local loading pattern in your area, but generally expect non-traditional westerly aspects to be the most suspect. Wind slabs may have formed further downslope of areas of stronger winds, a fact that may not be apparent until you've already committed to a slope. Â
Loose wet avalanches on steeper solar slopes should be possible during the warmest part of the day and on direct solar aspects. The sun is strong enough moving into early March to activate loose wet avalanches even on cooler days.Â
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.Â
Snowpack Discussion
A warm and wet start to February, was followed by mostly fair weather through mid-February, leading to generally thick surface crusts, as well as further deterioration of the snow cover below treeline.Â
After some light snow accumulations midweek along the west slopes midweek, 6-10 inches of new snow accumulated Thursday night and Friday above 4000 ft from Snoqualmie Pass and south, including Crystal Mt and Mt. Rainier. Much less new snow was received from Stevens Pass to Mt Baker, where only an inch or so fell. Â
Professional NWAC observer Jermey Allyn was at Paradise on Friday and found 25 cm (10 in.)  of new snow bonding well to previous snowfall received midweek and layering with a favorable density profile. By mid-day Friday, east winds were beginning significant snow transport near treeline and fresh wind slabs were developing on westerly aspects.Â
Gusty and strong E-NE winds were visibly seen transporting surface snow on the Mt Rainier camera Saturday, mostly at higher elevations, though the east sides of trees were void of snow near treeline confirming the winds earlier affects.  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
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, South, South West, West, North West.
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.
Aspects: South East, South, South West, West.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1 - 1