Avalanche Forecast

Sunshine or filtered sunshine through high clouds is expected Sunday with significant warming.  

Watch for recent new wind slabs at higher elevations, especially below ridges in easterly facing terrain. Watch for any wind deposited snow, however, such as cross loaded slopes or specific terrain features. 

Sunshine and warm temperatures Sunday should make loose wet avalanches possible on steep southerly slopes facing the sun.    

Some slopes exposed to recent winds or where less new snow was received after rain changed to snow, may have a very slick crust. Be cautious of uncontrolled falls if traveling on steep slopes with slick crust. 

Weather and Snowpack

A strong storm cycle Friday, 2/3 through Monday 2/6 deposited 3-5 feet of snow along the west slopes of the Cascades. 

The great snow didn't last long as a strong SSW storm brought heavy rain to the west slopes of the Cascades (Mt. Baker, Crystal and Paradise) Wednesday afternoon and Thursday, with a mix of snow, sleet, freezing rain, and rain in the Cascade Passes. A strong cold frontal passage swept through the Cascades mid-day Thursday with bands of light to moderate showers in SW flow.

A switch to westerly flow brought a rise in temperatures in the Cascade Passes Thursday afternoon and night.  

Friday was windy with a slow cooling trend during the day. Light showers increased and generally became moderate in the afternoon before tapering Friday night.

Most areas along the west slopes of the Cascades received about 6-8 inches of new snow with the Baker area about 14 inches by Saturday morning. The Mt. Baker area had received the most snow with 13 inches recorded at Heather Meadows through 6 pm Friday.

The aftermath of this storm cycle left a very strong crust with whatever loose snow remains above following the rain changing to snow. This ranges from 6-16 inches where winds did not strip the new snow and expose a slick crust.  

Recent Observations

North

Mt. Baker pro-patrol reported that the cooling trend had quickly locked up the recent wet snow within the ski area. Strong W-SW winds were transporting snow to lee slopes and not bonding well to the new crust. 

Lee Lazzara was in the Mt Baker backcountry Saturday and reported a favorable increasing resistance profile in the storm snow over the very strong rain crust. Observations were not made in terrain where wind slabs more likely formed. 

Central

Stevens Pass pro-patrol and DOT reported a natural avalanche cycle Thursday morning with major paths running D2 - D3. The pro patrol also observed some natural activity off Skyline Ridge and heard an unusual report of a path running to the Nordic road in Mill Valley. A bit east of Stevens Pass, a large avalanche off of Dirty Face Peak knocked in a garage door of a house on the north shore of L. Wenatchee around 1130 am Thursday. 

On Thursday, Alpental pro-patrol reported a breakable freezing rain crust (i.e. less stout than the 1/17 IFrc) that made for tough ski conditions. Cornices along ridgelines weakened during the warming with some cornice breaks observed in the early afternoon. The cornice failures triggered some D1-D2 storm slabs below ridges.  

South

Crystal pro-patrol observed several loose wet slides up to size D2, all aspects, within the ski area Thursday. No large slab releases were produced with explosives, Thursday afternoon. Wet slabs estimated to be about 1 ft deep were observed from the ski area in Pickhandle Basin. 

White Pass reported similar conditions as the other Passes, with a freezing rain crust up to at least mid-mountain and very strong W-SW winds atop Pigtail Peak through Friday. 

Crystal pro-patrol reported minimal results during control work Friday except... when they used a 25 lb explosive on Powder Bowl. The result was an 8 ft crown, 150-200' wide, that broke down to facets 3" above the ground. While this slide isn't relatable to human triggering, everyone loves a photo of a big avalanche.

 Crystal Mt Pro-patrol, explosive triggered slab, 2-10-17. Photo, P. Dale