Avalanche Forecast

Sunny weather should be seen on Monday with light northwest winds and recent snow layers continuing to stabilize. 

Wind slab is replacing storm slab as our primary avalanche problem as storm snow will be more rapidly stabilizing.

Small to large wind slabs should remain most likely on NW through E aspects on Monday and should become more stubborn or difficult to trigger. Watch for areas of firmer, wind-transported snow, mainly on lee terrain features. 

Storm slab layers in the upper snowpack are still giving test results at multiple locations along the west slopes of the Cascades on Sunday. These layers should continue to heal on Monday, but may still be present in areas that had rapidly accumulating snow the past couple of days.

Wind and storm slab will be most likely in the Northwest Zone at Mt. Baker, where snowfall has been heaviest. Note that we have been through a heavy loading period in the Mt. Baker area and a lack of observations in the above tree line zone, makes conditions there more uncertain.

Loose dry avalanches are not listed as an avalanche problem type, but continue to watch for loose dry snow on steep terrain, where even a small avalanche of this type may be dangerous above terrain traps or where early season hazards exist.

Travel with a partner and keep them in sight and in communication in areas where there has been recent heavy snowfall due to tree well danger.

Remember that early season terrain hazards still exist, such as poorly covered rocks, vegetation and creeks, particularly at lower elevations.

Warm, wet weather before Thanksgiving caused wet snow and glide avalanches as well as significant snowpack consolidation. There are no snowpack concerns below the Thanksgiving crust and in general new snow received post-Thanksgiving has reportedly bonded well to the Thanksgiving crust. 

A series of frontal systems produced snow over the past week at all stations in the Cascades since the Thanksgiving warm period: Locations on the west side of the Cascade crest have received 1.5' to 4.5' with the most at Mt. Baker.

This includes the recent snow accumulation for the 48 hours ending on December 3 along the Cascade west slopes range from 5-27" with the most again at Mt. Baker.

Since about Monday November 27th, temperatures have generally been steady in the mid-to upper twenties and winds at higher elevations have been SW to WSW in the single digit to 20's range with some higher gusts, particularly in the south Cascades.

Observations

North

On Saturday morning, the Mt. Baker Ski Area reported widespread 10-14" touchy, large ski-triggered storm slab on all aspects along with a couple similarly sized natural avalanches. During the day, the resort also reported 3 close calls due to tree-well incidents.

By Saturday afternoon, an NWAC pro observer found that slab layers were becoming more stubborn to trigger.

On Sunday, the Mt. Baker ski patrol reported many folks were skiing in the backcountry with no avalanches reported. Additionally, a private report to NWAC indicated small, thin wind slab high on north-facing slopes near the Mt. Baker ski area. Otherwise, no signs of instability. Plenty of point releases on S-facing slopes during sun breaks.

On Sunday, a Professional Guide was skiing in the Bagley Lakes area and despite many back-country skiers, saw only one small triggered shallow wind slab in a steep, loaded location. Layers from Friday were less reactive and healing

Central

On Saturday, the Alpental Ski Patrol reported generally well-bonded settled snow.

On Sunday, NWAC observer Jeremy Allyn was in the Alpental/Source Lake area. A lot of recent storm snow hasn't fully settled and there were still some storm layers giving moderate RP results in snow pit tests. Pockets of wind affected snow seen on high terrain. The low-density snow was deep and tree wells were a major hazard. 

South

NWAC Pro Observer Dallas Glass was out on Saturday in the Paradise area. On W-S-E aspects he found  8” new of new snow well-bonded to 2 feet of previous snow on the Thanksgiving crust. He found 5400-6000’ W-SW-S-SE-E. He did not find evidence of storm or wind slab. 

On Sunday, Crystal Mountain Ski Patrol reported 10” of new snow in the last 24 hours. The upper snowpack is generally right-side up and well-bonded to the Thanksgiving day crust. Winds on Saturday night also created a shallow surface layer of higher density snow giving minor cracking and likely small, shallow areas of wind slab.

Another Pro Observer was at Paradise on Sunday where the main story was the 9-10" of new snow that fell at slightly higher densities and precipitation rates, giving small storm slab on varied aspects. Several small loose-dry avalanches were observed in the near tree-line.