Plan your day around avoiding sun-exposed slopes and cornices at peak daytime warming. Wet loose avalanches are possible, especially from southerly slopes and terrain features.
Summary
Confidence
Moderate - Uncertainty is due to the timing or intensity of solar radiation and its effect on the snowpack. Uncertainty is due to the limited number of field observations.
Weather Forecast
Overnight Wednesday: Mostly cloudy. Light northeast wind and freezing levels dropping to the valley bottom.Â
Thursday: Mix of sun and cloud. Ridgetop wind light from the northeast. Alpine temperatures near -1 and freezing levels 1500 m.Â
Friday: A mix of sun and cloud. Light winds from the East. Alpine temperatures near -2 and freezing levels 1500 m.
Saturday: Snow 10-20 cm. Alpine temperatures near -4 and freezing levels 1400 m.Â
Avalanche Summary
No new avalanche reports in this region since last weekend. In the neighboring South Coast Inland large wet slabs were reported from southerly aspects up to size 3.5 and ongoing wet loose avalanches have occurred up to size 2.Â
Last 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 the valley bottom.
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As the weather pattern changes and the temperatures drop, I suspect a decrease in natural avalanche activity. However, solar slopes remain suspect when the sun is shining. It can really pack a punch this time of year, even for short periods of time.Â
Snowpack Summary
A solid melt-freeze crust exists to the mountain top on solar slopes and up to 2000 m on polar slopes. Above 2000 m on North facing terrain, you may find dry snow and a generally well-settled snowpack. Below treeline elevations, the snowpack has been isothermal but will likely lock up as freezing levels drop.Â
Cornices are large and looming along ridgelines. They are weak and very unpredictable.Â
Terrain and Travel
- Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.
- Back off slopes as the surface becomes moist or wet with rising temperatures.
- When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.
- Keep in mind that wet avalanches can be destructive due to their high density.
Problems
Loose Wet
Wet loose avalanche activity is possible on sun-exposed slopes. 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 22nd, 2021 4:00PM
