Avalanche Forecast

Decreasing winds and mostly light snow showers should be seen over the Cascade west slopes on Saturday with much lower snow levels and much cooler temperatures. Not a lot of snow is expected following the front Friday but we will see how it goes. The avalanche danger should decrease on Saturday but the decrease will be a moving target and careful snowpack evaluation and cautious routefinding will be essential.

Layers of recent or new wind and storm slab may need a day to mostly stabilize. Water may also need a day to drain from the upper snow pack below about 3-4000 feet.

Recent moderate to strong southwest to west winds will make wind slab most likely on northwest to southeast slopes but keep an eye out on all aspects in areas of more complex terrain. Watch for firmer wind transported snow from Friday and possible deeper wind transported layers such as from Tuesday.

New storm slab formed on Friday may need a day to mostly stabilize on Saturday. Storm slab is most likely in area that experienced more than a few hours of rapidly accumulating snow.

Cornices won't be listed as an avalanche problem in this area but avoid areas on ridges and mountain tops were a cornice might be present and avoid slopes below cornices.

Weather and Snowpack

The most recent wet warm storm arrived on Valentines Day 2/14 and formed the uppermost, very strong rain crust in the snowpack. 

A series of disturbances in cool, NW flow aloft from Saturday 2/25 through Tuesday 2/28 deposited 1.5 - 3.5 feet of snow along the west slopes of the Cascades. Very strong alpine west winds were seen in most of the Olympics and Cascades on Tuesday.

Southwest flow aloft began to ramp up again on Thursday as the first in a new series of fronts crossed the Northwest. Strong southwest flow is carrying a second stronger front across the Northwest on Friday evening. Along the Cascade west slopes this will be causing strong southwest alpine winds, heavy, moist, dense new snow above about 3-4000 ft and wet snow or rain below about 3-4000 ft. An avalanche cycle is expected in many areas along the Cascade west slopes Friday afternoon and evening.

Recent Observations

North

NWAC observer Lee Lazzara reported that extensive avalanche control was needed at the Mt Baker ski area on Friday but further detail are not currently available. Lee found an upside down warmer, wetter over drier, weaker profile and that test columns were failing on isolation in storm snow layers. A general top of the snowpack profile was 30-40 cm of 1F+ over 4F snow.

Central

NWAC observer Jeremy Allyn was in the Alpental Valley on Thursday and found storm snow instabilities still present and slowly stabilizing. Thin wind slab was forming in the upper portion of the below treeline band and showed signs of increasing sensitivity.

The Stevens patrol reported widespread 6-8" ski triggered storm slab on Friday morning. Sensitive loose wet ski tests were also seen below about 4500 ft.

NWAC observer was also at the Stevens ski area on a day off from the NWAC but reported upside down wetter over drier snow conditions.

Extensive 4-14" wind slab triggered by explosive control turned into wet debris at Alpental on Friday morning.

South

No recent observations.