Avalanche Forecast

Mild snow levels should keep precipitation in liquid form until a cold front passes through the Cascades Friday mid-afternoon with snow levels lowering to 4000-4500 feet by late afternoon.  Precipitation should be light to moderate, except occasionally heavy in the Mt. Baker area Friday afternoon through evening. 

Rainfall will renew the loose wet potential on all aspects of steeper slopes. New snowfall should bond well to a moist snow surface in most locations, but wind-driven snow may build unstable wind slab on lee aspects of higher terrain by late Friday afternoon. 

Continue to watch for loose wet avalanche potential above terrain traps such as above cliffs, near gullies or where avalanche debris would deeply accumulate. These are the types of places that even small wet avalanches can have serious unintended consequences.

Avoid cornices along ridges and slopes below cornices since cornices may still be weaker due to the warm weather.

Glide avalanches occur when a smooth bed surface (ex.rock face) becomes lubricated by water and the wet slab above releases. They are not tied to specific air temperature or rainfall trends other than they occur during or after prolonged mild conditions, similar to what we have experienced over the last several days. Be aware that even with dropping snow levels Friday, powerful glide avalanches are possible in the right terrain features until we have an extended period of cold weather.   

Weather and Snowpack

A large upper ridge and warm air mass aloft over the West Coast from this past Sunday through Wednesday led to the warmest weather of the winter. During this stretch temperatures were generally well above freezing. Freezing levels came down a few notches Thursday, but mild conditions continued with spotty light rain increasing Thursday afternoon. 

The very warm temperatures and solar effects caused loose wet avalanches, snowpack consolidation, and melt-freeze surface crusts. This will have further stabilized the lower and mid snow pack and turned the most recent storm snow into moist to wet snow in most areas. The upper snowpack should be well bonded to the 1/28 rain crust in all areas. 

Recent Observations

NWAC pro-observer Ian Nicholson was in the Snoqualmie Pass backcountry on Tuesday and reported that an extensive loose wet avalanche cycle with some large avalanches had occurred on Monday. In the same area, only a few small natural loose wet avalanches were seen on Tuesday. The Alpental pro-patrol gave a similar report for Tuesday.

Another sign of the ongoing warmth, both the Alpental and Mt. Baker pro-patrol reported glide cracks with small glide avalanches releasing off of steeper rock faces within their respective areas Thursday.