Avalanche Forecast

On Tuesday a front crosses the Cascades in the afternoon, causing increased winds, initial warming followed by cooling, with the northeast Cascades likely getting the most new snow.

This weather is likely to build new denser storm and wind slab on previous snow from Sunday night. Storm snow avalanches should primarily involve snow from Sunday night and new snow. These layers lie on a moist to wet older snowpack, which may provide a bed surface. Underlying older snow should continue to gain strength.

The avalanche danger should increase during the day Wednesday, mainly near and above treeline. 

Watch for the numerous travel hazards such as open creeks, barely buried rocks and trees, and glide cracks, creating poor and challenging travel conditions, especially below treeline. 

Mainly outside of Washington Pass, much of the below treeline elevation band does not have enough snow cover to support an avalanche hazard. 

Remember that closed ski areas without avalanche mitigation are equivalent to backcountry terrain!  

The great start to the 2017/18 PNW Winter hit the pause button last week in the Washington Pass area with only small fluctuations in total snow depth at the Pass during this incredibly active period. During an extended period of warmth and wet weather in the days leading into Thanksgiving, an initial round of wet snow and glide avalanches occurred, especially on steep unsupported slopes and rock faces. 

Over the weekend, the weather system that brought rain to the rest of the Cascades brought several inches of snow Saturday night through Sunday at Washington Pass. Mixed precipitation or a brief period of rain may have occurred Sunday afternoon as temperatures warmed aloft.  

Little to no new snowfall was seen for most of the central-east and southeast Cascades over the weekend due to warmer temperatures and a period of rain. Snow depths are also lower in these areas.

A front and a splitting upper trough crossed the US west coast Sunday and Sunday night. Along the Cascade East slopes, temperatures generally dropped from near or above freezing to the 10's and 20's. New snow amounts were T-3" on Monday morning with the most at Harts and Washington passes. The only wind observations from NWAC stations along the Cascade east slopes are from Washington Pass where winds shifted from SW 20's to WSW 10's.

Observations

See the recent observations tab for reports of several wet snow avalanches near the WA Pass area as a result of the warming and rain early last week.