Avalanche Forecast

A few isolated snow showers may linger Monday, while winds should be light and temperatures remain cool. 

This should allow for a slowly improving avalanche danger as recent storm and wind slabs begin settling and stabilizing.

However, storm and wind slab conditions should remain sensitive or still likely to trigger in specific areas and more widespread areas near and above treeline. A variety of slopes may be wind loaded due to the local effects of terrain, however, in general wind loaded slopes should range from north to southeast facing.  

Dangerous avalanche conditions are expected near and above tree line requiring conservative decision-making and cautious routefinding.

Be cautious with any steeper open terrain suspected of recent wind loading, leaving those more exposed features a wide margin of safety.

Travel conservatively by staying off, or below steep open slopes and avoiding the wind loaded terrain near and above treeline.

Be aware of early season hazards below treeline. The heavy rains from last week have left many creeks open at lower elevations. 

Snowfall over the west slopes the first week of December ranged from 1-4 feet. An atmospheric river arrived early in the week and heavy rain fell over the west slopes, with water amounts ranging from about 5 to 8.5 inches in just 2 days ending Wednesday morning!  Since Wednesday, 15-40 inches of new snow had accumulated along the west slopes through Sunday afternoon. 

Avalanche and Snowpack Observations

The warming and rain or heavy wet snowfall a week ago did cause avalanches and some very close calls with slides releasing on persistent weak layers above the mid-November crust. It's important to remember when looking at the snow in more protected areas  and trying to extrapolate those findings to adjacent to open avalanche prone slopes that may have avalanched recently, possibly multiple times! The snow structure of those paths may be significantly different than where you may have chosen to dig in the snow.

Persistent weak layers in the Stevens and Snoqualmie zones should have been eliminated and multiple test results this weekend from field observers have not found that layer in test results. Therefore, the persistent slab problem has been removed from the forecast problems.  

Reports Sunday varied according to recent wind exposure during the last few days storm cycles. Multiple reports from the Skyline Ridge area near Stevens Pass, indicated relatively homogenous storm snow, well bonded to Tuesday's rain crust. No slab structure was noted in that area and good skiing was noted with some 30-50 cm or up to 2 feet of storm snow over the recent rain crust. However, across the street in the ski area, morning control produced widespread soft slab results from both explosive and ski cuts with best results on NW-SE facing terrain with slides releasing on the most recent storm interface with Friday's storm snow.

Elsewhere, from patrol at Mt Baker and Alpental Sunday, report widespread avalanches released from explosives ranging from 1-2 feet and running good distances, releasing on storm snow interfaces.