Avalanche Forecast
Regions: Cascades - South West.
Watch for melting and weakening of surface snow layers and potentially weakening cornices.
Detailed Forecast
Light winds, mostly sunny weather and mild daytime temperatures are expected Saturday.Â
Most areas do not have sufficient loose surface snow to become wet and easily available for wet snow avalanches, however, sunshine and warm afternoon temperatures should maintain somewhat of a loose wet avalanche problem on Saturday. Watch for wet snow deeper than a few inches or rollerballs or pinwheels on steep solar slopes. The problem of loose wet avalanches should not be extensive, but limit your terrain choices if you see more activity than expected.
Cornices are not listed as an expected problem, but may begin to weaken during the warmest part of the day so it's time to be practicing checking the ridges as we shift into spring.
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
The last snowfall in the Cascades was late last week when about 8-13 inches fell near and above treeline west of the crest from Snoqualmie to Mt Rainier with less elsewhere along the west slopes.
This was followed by local strong northeast winds in the Cascades last Friday and Saturday.
Few recent observations have been made over the past few days, however NWAC pro-observer Jeremy Allyn was at Paradise on last Friday and found 10 inches of new snow, that NE winds were transporting and forming fresh wind slabs on west aspects. See his video on the NWAC Instagram account. The Crystal ski patrol also reported a small 1.5 foot skier triggered wind slab on Saturday due to cross loading at 6850 feet.Â
NWAC pro-observer Jeff Hambelton was at Mt Baker a week ago Saturday where there was less recent snow and reported no evidence of instability near and below treeline.
Jeremy Allyn was back out at Crystal on Sunday and reported many skiers and no avalanches. A report via Turns All Year for Mt St Helens Sunday reported wind slab, but no sign of propagation and they did not tempt steeper slopes.
Cooler weather Sunday and Monday was followed by sunny and gradually warmer weather this week. Mountain temperatures were mainly in the 40's to low 50's at many NWAC stations Friday afternoon. This should have stabilized any small wind slab layers formed late last week.
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.
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Avalanche Problems
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: Possible
Expected Size: 1 - 1