Avalanche Forecast

Moderate - Forecast snowfall amounts are uncertain on Monday

10-15cm of new snow is expected between Sunday night and Monday morning. On Monday, expect mainly cloudy skies, light snowfall and the odd sunny break. Moderate mixed rain and snow (up to 15mm each day) is forecast for Tuesday and Wednesday. Ridgetop winds should be strong from the southwest on Monday, and the become extreme and southwesterly on Tuesday and Wednesday. Freezing levels will yo-yo from 1500m on Sunday night to about 1200m by Monday afternoon and Tuesday morning. From there, the freezing level will gradually spike to about 1800m by Wednesday evening.

Over the past week, loose wet avalanches, cornice failures, and deeper persistent slab avalanches to size 3 were observed failing naturally in response to warming and solar radiation. With snow and wind expected throughout the forecast period, we are shifting back to a general pattern of storm slab avalanche activity. That said, spring-like loose wet avalanches, isolated persistent slab avalanches and cornice failures will still be possible at elevations where precipitation falls as rain or during periods of warming and solar radiation.

By Monday morning, 5-15 cm of new snow is expected to overlie a widespread melt-freeze crust. Below about 1300m, light rain is expected to further saturate the snowpack keeping the snow loose and unconsolidated. The warm temperatures and sun over the last week woke up deeply buried weak layers within the snowpack. This includes a weak crust/surface hoar layer which was buried down 20-30cm in the north of the region, a widespread crust/facet layer buried in early February down up to 1m, a lingering surface hoar layer from January down around a meter, and weak basal facets at the bottom of the snowpack. Cooling should dramatically limit the reactivity of these old layers; however, they may come back to life during future periods of warming, heavy rain or solar radiation.