Avalanche Forecast

A southwest-northeast oriented front will move slowly to the International border area on Thursday with a series of waves beginning to move along the front. This should cause new snow above treeline and rain near and below treeline in the north Cascades Thursday afternoon. But the central and south Cascades should remain dry through the daylight hours on Thursday.

So the main change to watch for will be in the northwest Cascades Thursday afternoon. In these areas above treeline watch for new wind and new storm slab to develop if there is more than several inches of new snow by the end of the daylight hours. Less new snow will mean less of an increase in new wind and storm slab avalanche danger.

Further snow above treeline and rain near and below treeline should be seen in the northwest Cascades Thursday night.

In all areas west of the crest Thursday watch for previous shallow wind slab on previous lee slopes. Loose wet avalanches should also remain possible especially on solar slopes.

Less recent snow and ample terrain anchors should greatly limit the avalanche danger below treeline. 

Remember the NWAC forecast applies to elevations up to the Cascade crest (~7000 to 8000 ft). Significant new snowfall was received above these elevations on the volcanoes over the weekend and this likely poses a higher avalanche danger.  

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 to cause an avalanche danger.

Last weekend another warm and wet system brought a one-two punch to the Pacific Northwest. The initial system Saturday brought 1.5 - 2.5 inches of rain with the snow line around 6000-7000 ft. On Sunday a second low pressure system deposited about 8-16 inches of snow above 4500 feet in the north Cascades and above about 6000 feet in the south Cascades. Significantly less new snow was received below these elevations.

A weak front then caused about 1-3 inches of new snow above about 5-6000 feet in the south Cascades on Tuesday.

NWAC observer Dallas Glass was at Paradise Sunday and saw a climber trigger a loose wet avalanche, size 2, on a steep slope at 6500 feet near treeline (no injuries). He also witnessed skier triggered moist storm slabs and loose wet avalanches in the near treeline band involving the 10-12 inches of new storm snow.

NWAC observer Jeff Hambleton was at Mt Baker on Monday and reported 12-18 inches of storm snow with recent and witnessed natural and triggered storm slab and wet loose size 1-1.5 avalanches.

The Chinook DOT crew on Monday found debris from an natural cycle of loose or storm slab avalanches from Sunday.

Evidence Monday, March 16th of storm avalanches on Sunday on Naches Peak. Photo J. Stimberis.

NWAC observer Tom Curtis was on Nason Ridge near Stevens Pass on Wednesday and found ongoing possible loose wet avalanche conditions on solar slopes and lingering shallow wind slab on northwest to northeast slopes. 

The snowpack at low elevations remains meager to non-existent with the average snow-line around 4500 feet along the west slopes. The mid and lower snowpack west of the crest consists of layers of stable consolidated rounded grains or melt forms and crusts from multiple warm periods this winter.