Avalanche Forecast

Tuesday: Many naturally occurring loose wet avalanches have been observed mostly large (size 2) typically located at elevations, Treeline, and below. In the alpine, skier trigger small avalanches (size 1) have occurred and these avalanches were described as loose and dry.

Monday: A widespread natural avalanche cycle occurred during yesterday's storm event. A variety of avalanche sizes were observed from small (size 1) to very large (size 3). Even during limited visibility, the extent of the activity was notably high.

Sunday: A relatively quiet day for avalanche observations and reporting. Explosive control produced limited small (size 1 to 1.5) results.

Saturday: Numerous large (size 2) wind slab and storm slab avalanches have been reported. These avalanches were located on north aspect terrain between the elevation bands of 1400 to 1600 m. A few of them were naturally initiated with most being either explosive or ski-cut triggered.

Friday: Another round of ongoing avalanche occurrences has been reported, as visibility has been limited these reports suggest that many more have been occurring. Numerous both natural and explosive triggered large (size 2-2.5) have been reported. These avalanches have all initiated within the 1500 - 1600 m range just below ridgetop features. One very large (size 3) avalanche ran 1000 m in length and the common theme of running far and fast due to firm surface conditions has been a common theme. A rain-on-snow event triggered loose wet avalanches 1300 m and below.

Riders should exercise restraint and patience as the current warming and wet conditions maintain a high danger rating. Choose simple non-avalanche terrain that is low-angle and well-supported. Avoid steep and wind-loaded areas at upper elevations. Keep in mind the potential for deeper instabilities to produce large and surprising avalanches that will run far and fast.

Freezing levels reached nearly 2500 meters on Wednesday. This factor combined with light precipitation in the form of rain has settled and moistened the upper snowpack adding additional weight and stress. Large cornice features with weak tabs and noses are present on mostly North aspect terrain in the alpine.

A weak layer of surface hoar buried in early January is now down 70-100 cm. During testing on Tuesday, this layer was producing hard but sudden planar results down 100 cm. This layer is spotty in its distribution and is of greatest concern in sheltered and shaded openings at treeline.

Weak layers that were reactive over the Christmas and New Year's period have shown signs of bonding and gaining strength. These include a surface hoar layer buried on Dec 28 found 50 to 100 cm deep and a facet layer buried on Dec 23 found 70 to 120 cm deep.

Wednesday night

Cloudy with rain and snowfall, 5 cm of accumulation. Alpine temperatures 1 °C. Ridge wind southwest 60 km/h. Freezing level 1800 m.

Thursday

Cloudy with light rain and snowfall, 1 to 3 amounts of accumulation. Alpine temperatures 0 °C. Ridge wind west 50 km/h. Freezing level of 1500 m descends to 1000 m.

Cloudy with very light rain and snowfall, trace amounts of accumulation. Alpine temperatures -2 °C. Ridge wind northwest 50 km/h. Freezing level 500 m.

Cloudy with very light rain and snowfall, trace amounts of accumulation. Alpine temperatures -3 °C to -8 °C. Ridge wind northwest 50 km/h. Freezing level 500 m descending to 0 m.

More details can be found in the Mountain Weather Forecast.

• Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
• Be aware of the potential for surprisingly large avalanches due to deeply buried weak layers.
• Minimize your exposure time below cornices.
• Extra caution for areas experiencing rapidly warming temperatures for the first time.