West Slopes North

A five-day stretch of sunshine and abnormally warm temperatures will end Sunday marking the transition to a more active weather pattern. Generally safe avalanche conditions will exist where you encounter firm and frozen snow surfaces. Even though avalanches will be unlikely, watch for signs of instability during periods of rain and in wind-loaded terrain high in the alpine. 

A weak frontal system will bring cooling temperatures and light precipitation (4500-5500ft snow levels) by Sunday morning. Expect cloudy skies and light rain in most areas with not enough high elevation snow to create new avalanche problems. Snow surfaces at mid and lower elevations may not experience a solid overnight freeze and have the best chance of becoming wet and weak. With any incoming rain during the day, watch for signs of instability like roller balls and pinwheels. High in the alpine, look carefully for evidence of wind drifted snow before committing to steeper terrain.

Despite the short days and low angle of the sun in December, solar radiation and unseasonably warm air significantly impacted the snowpack this week. The Pan Dome weather station (5020ft) at Mt. Baker Ski Area recorded steady temperatures of 35-50F since Tuesday night (12/1). During this time, observers reported small but widespread wet avalanche activity, even extending to northerly aspects at upper elevations. The wet avalanche cycle peaked on Wednesday during the initial warm-up, but minor wet loose activity continued through Saturday on steep, sun-exposed slopes. Glide cracks and small glide avalanches were reported as well in areas where thin snow covers smooth rock surfaces. Fortunately, the snowpack was resilient to all the heat with only a few inches of snowpack settlement and even reports of dry snow lingering on shaded upper elevation slopes. 

Snow depths range from 40-70 inches in the Mt. Baker area, and continuous snow begins near 2500-3000ft. Current snow coverage is well above average for December (Snow Depth Climatology), but early season conditions still exist. Many lakes and creeks are still open, and plenty of hidden obstacles lurk just below the snow surface. 

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.