Avalanche Forecast

On Tuesday a front crosses the Cascades in the afternoon, causing increased winds, initial warming followed by cooling, with Baker and Paradise 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.

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. 

The avalanche danger should increase during the day Wednesday for all elevation bands.

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

The great start to the 2017/18 PNW Winter took a giant step backwards over the last week. 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. Another round of rain Saturday night through mid-day Sunday likely did not cause widespread wet snow avalanches on an already beat up and saturated snowpack. This warm, wet and windy period melted significant snow with total snow depths decreasing by 50% or more from their mid-November peak depths at many NWAC stations. 

A front and a splitting upper trough crossed the US west coast Sunday and Sunday night. Along the Cascade West slopes, the passage of a sharp cold front on Sunday brought SW-W winds of 40-50 mph with gusts into the 70's and 80's at some higher elevation NWAC stations which decreased into the 10-20 mph range. Temperatures generally dropped from the 30's and 40's into the 20's on Sunday afternoon. New snow amounts were fairly light ending Monday morning, ranging from 0-5". 

Lingering light snow showers were seen on Monday at continued cooler temperatures, with lighter winds.

Observations

On Monday morning, Mt. Baker Ski Area reported 8-10" of right side up low density snow, well bonded to previous wet snow. Avalanche control yielded only small loose dry snow avalanches. Wind loading was not significant.

On Monday, Professional Observers Dallas Glass and Jeremy Allyn traveled into the Crystal backcountry. They also found 3-4" of new snow moderately well bonded to the old moist to wet snow interface. The old wet snow is beginning to refreeze. It is supportive to skis, but not boots. They ski triggered a small loose wet avalanche on a directly sun-exposed south-facing slope. They also noted minimal wind effects.