Avalanche Forecast

Moderate - Forecast snowfall amounts are uncertain on Monday

Between 5-20mm of precipitation will fall between Sunday night and Monday. Expect a mix of sun and cloud on Tuesday and generally clear skies on Wednesday. Ridgetop winds will be strong from the southwest on Sunday night and Monday, and then remain light for the rest of the forecast period. Freezing levels are expected to sit at 2300m on Sunday night and then drop to 1400m for Monday and Tuesday. Freezing levels will then shoot back up to 2900m with Wednesday's clear weather.

Recent observations have been extremely limited; however, in the neighboring Sea to Sky region wet slab, loose wet and cornice avalanches to size 3 were triggered naturally by warming and solar radiation. On Monday there will be a shift to more wintery avalanche problems. New snow and wind are forecast to spark a round of fresh storm slab activity in high elevation lee terrain.

By Monday morning light to locally moderate amounts of snow are expected to have fallen. Due to the temperature trend in the storm (warm to cold), my feeling is the new snow will develop a reasonable bond to older surfaces which should include a mix of hard crusts on high elevation solar aspects, settled dry snow in high north-facing terrain, and moist snow everywhere else. Strong to extreme southwest winds should accompany the storm, so I would expect relatively short-lived yet potentially deep weaknesses to exist with the new snow, especially in high elevation lee terrain. The storm will also encourage ongoing cornice development and newly formed cornice tabs are expected to be sensitive to triggering. Below the new snow, the snowpack is generally strong and well-settled. The exception may be in the Duffey area where professionals are tracking a layer of facets down over 1m which likely resulted in a couple deep persistent avalanches which were reported during last week's warm-up. With forecast cooling on Monday and Tuesday, this layer should become dormant (until the next warm spell).