Avalanche Forecast

Moderate -

Sunday night: Heavy snowfall bringing 30-40 cm of new snow. Rain below about 1100 metres. Strong to extreme south winds.Monday: Continuing snowfall bringing 20-30 cm of new snow. Rain below about 1100 metres. Strong to extreme southwest winds. Freezing level to about 1500 metres with alpine high temperatures around -2.Tuesday: Cloudy with continuing flurries bringing approximately 5 cm of new snow. Moderate southwest winds. Freezing level to 900 metres with alpine high temperatures of -6.Wednesday: Mainly cloudy with isolated flurries and a trace of new snow. Light west winds. Freezing level to 700 metres with alpine high temperatures of -7.

Reports from Saturday showed explosives control in the Whistler area producing numerous storm slab results from Size 1.5-2, as well as several Size 1.5 cornice releases.Throughout this region there has been evidence of a natural avalanche cycle up to size 3 that occurred within the storm snow on Wednesday. More notable are the numerous explosive triggered, very large avalanches up to size 3.5 that where reported near Whistler on Thursday. Two additional explosive triggered 3.5's were reported Friday. These avalanches started in the storm snow and then stepped down to the early January and even the mid-December crusts which resulted in very large avalanches running full path. They occurred on northwesterly aspects below rocky ridgetops between 1950-2200 m. Although these layers are over 200 cm beneath the snow surface, a large trigger such as a falling cornice or a smaller human triggered avalanche has the potential to "step-down" to these layers, which would result in a large and destructive avalanche.

Another 10-20 cm of new snow on Sunday morning brings recent storm totals to around 90-120 cm. This snow continues to be redistributed by strong southeasterly winds, creating dense storm slabs in lee and cross-loaded features. Impressive cornice growth has also been observed on the lee side of ridgetops. A crust that was buried in early January is buried 200-250cm below the surface at all elevations. Below this there is another crust which was buried in mid-December. Recent explosive control work has triggered storm slab avalanches that have "stepped down" to both of these crusts, resulting in very large avalanches running full path. Although these layers are over 200 cm beneath the snow surface, continued potential exists for large triggers such as a falling cornice or a smaller human triggered avalanche to "step-down" to these layers. This would result in a very large and destructive avalanche.