Start (and finish) your day early to avoid exposure to sun-exposed avalanche terrain. Steer clear of cornices overhead and plan your egress route carefully.
Summary
Confidence
High - Confidence is due to a stable weather pattern; little change is expected for several days.
Weather Forecast
Sunday night - Clear / light to moderate northeast wind / alpine low temperature 0 / freezing level dropping to 2500 m. Areas further inland like Whistler may see freezing levels drop to 1200 m overnight.
Monday - Sunny / light wind / alpine high temperature near 0 / freezing level 2300 m
Tuesday - Sunny / light wind / alpine high temperature near +1 / freezing level 2500 m
Wednesday - Sunny / light wind / alpine high temperature near +2 / freezing level 2600 m
Avalanche Summary
Over the weekend, multiple large to very large wet slab avalanches were observed near Whistler, size 2-4. Many of these involved the full depth of the snowpack, running to valley bottom.
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Solar triggered wet loose avalanches have been reported each day over the past week up to size 2.5. There have also been a number of cornice failures reported over the past week.
Snowpack Summary
Radiant cooling and (finally) a slight dip in freezing levels overnight have likely formed a thin surface crust in many areas. It should quickly soften during they day with sunshine and warm temperatures. Steep north aspects at the highest elevations may still hold dry snow.
Cornices are large and looming along ridgelines. Sun and warm temperatures will increase the chances of cornice failures, especially when temperatures remain above zero overnight.
Terrain and Travel
- Avalanche hazard is expected to to increase througout the day, think carefully about your egress.
- Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
- Keep in mind that wet avalanches can be destructive due to their high density.
- Avoid lingering or regrouping in runout zones.
Problems
Wet Slabs
The likelihood of wet slab avalanches increases during prolonged periods of warm temperatures, as the heat penetrates deeper into the snowpack. Multiple very large wet slab avalanches have been observed in the last couple days. These avalanches are dense, destructive and can run far, reaching otherwise snow-free valley bottoms.
Wet loose avalanche activity can also be expected on sun exposed slopes and below treeline. These avalanches are generally smaller than wet slabs but they can gather mass as they travel and reach low elevations.
Aspects: East, South East, South, South West, West.
Elevations: All elevations.
Likelihood
Expected Size
Cornices
Cornices are at their largest at this time of year, and become weaker with warm temperatures and solar radiation.
Aspects: North, North East, East, West, North West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Apr 19th, 2021 4:00PM
