East Slopes South

Extreme winds have built fresh and sensitive wind slabs with the recent heavy snowfall. You will be able to trigger a large avalanche on lee slopes steeper than 35 degrees. Choose lower-angle terrain where you find wind stiffened or textured snow and avoid travel under and near cornices, which are sensitive and likely to fail.

Wind-affected snow should be easy to find in every elevation band on Saturday.  Fresh wind slabs will likely form further below ridgelines and even on open slopes below treeline.  Avoid all wind-loaded slopes steeper than 35 degrees Wednesday where you are likely to trigger a wind slab avalanche. Cornices will be large and may be easy to trigger along ridgelines.  Give them a wide berth as they often break further back than you expect.  

Under sunny skies Wednesday, observers just east of White Pass surveyed the surrounding Tieton and American River drainages, seeing evidence of recent large avalanches that released earlier in the week.  The avalanches were not as deep or widespread as in zones further north near and east of the Cascade crest.  We still have plenty of uncertainty about deeper weaker layers that may exist in the snowpack.  Limit your exposure to large avalanche paths throughout the upcoming storm cycle.  

Sun breaks are likely Saturday. Where the sun shines, loose wet avalanches will be likely. Look for rollerballs on the snow surface, water dripping from trees, and trees shedding snow as the first sign that the snow surface is becoming weak. If you see these signs, choose terrain less than 35 degrees in angle and move towards shadier slopes and use extra caution above terrain traps like cliffs and creeks. Some areas of the mountain may not get sunshine. If you aren't experiencing sunshine and don't see noticeable wind effects, consider storm slabs to be your main concern.

An atmospheric river event began Saturday night and lasted through Monday with gradually rising temperatures peaking late Monday morning, pushing rain up to at least 6000' in the zone.  A stout melt-freeze crust will likely be found (2/22) under the most recent snow near and below treeline, but this crust may phase out above treeline.   A thinner sun crust likely formed on steep southerly aspects Wednesday.  Winds at the neighboring White Pass 6000' station showed gusts up to 100 mph Monday evening and remained strong to extreme out of the west through Tuesday.  Over a 3 day period, Snotels have averaged about 1.00 -1.80 of water across the zone. 

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.