Avalanche Forecast
Regions: Cascades - West.
Watch for wet surface snow on steep solar slopes that could lead to loose wet avalanches and potentially weakening cornices.
Detailed Forecast
Light winds, mostly sunny weather and mild daytime temperatures are expected again Sunday. This should not bring much change to hard or firm or stable old snow in most areas.
Most areas do not have sufficient loose surface snow to become wet and easily available for wet snow avalanches. But sunshine and warm afternoon temperatures will thaw and melt some snow Sunday midday and afternoon. 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 is becoming a fading memory and was near the end of February 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 at the end of February. Local wind slab formed and was triggered at that time on west aspects such as seen by NWAC pro-observer Jeremy Allyn at Paradise and the Crystal ski patrol.Â
Sunny and gradually warmer weather has been seen the first week of March. This will have stabilized wind slab from the end of February and further consolidated the snowpack. Recent reports throughout the Cascades generally indicate hard or firm or stable old snow. There was almost no snowfall in January and February and none so far in March. The snowpack at lower elevations is meager to non-existent and way below normal. There have not been any reports of significant avalanches for a long time. Some folks are finding a bit of cool old snow surviving on some north to east slopes at high elevations.
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