Avoid sun-exposed avalanche terrain. Loose wet avalanches and wet slab avalanches often result from surface layers reaching 0 degrees. As deeper layers of the snowpack begin to melt, larger avalanches become possible.
Steer clear of cornices from above and below.
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: Clear with cloudy periods. Light northeast wind. Alpine temperatures +5 and freezing levels 2000 m.Â
Thursday: Mix of sun and cloud. Ridgetop wind light from the northeast. Alpine temperatures near +7 and freezing level 1900 m.Â
Friday: A mix of sun and cloud. Light winds from the South. Alpine temperatures near -2 and freezing levels 1600 m.
Saturday: Precipitation 10-20 mm. Alpine temperatures near +1 and freezing levels 1200 m. Â
Avalanche Summary
No recent avalanche observations have been submitted from this region.
In the neighboring Sea to Sky region and the South Coast Inland, multiple wet slab avalanches were observed over the weekend and as of Monday, size 2-4. Many of these involved the full depth of the snowpack, running to the valley bottom. We suspect similar activity to have occurred in the South Coast region as well.
Snowpack Summary
High overnight freezing levels continue, meaning that the snow surface remains moist or wet. In places where the surface forms a crust overnight, it should quickly soften during the day with sunshine and warm temperatures, but in most places below treeline, I suspect mostly isothermal conditions exist and the snowpack is diminishing quickly. The highest elevation north aspects (above 2200 m) may still hold some dry snow.
Cornices are large and looming along ridgelines. They are weak and very unpredictable.
Terrain and Travel
- 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
Loose Wet
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
Wet Slabs
The likelihood of wet slab avalanches increases during prolonged periods of warm temperatures, as the heat penetrates deeper into the snowpack. In the neighboring Sea to Sky Region and South Coast Inland several very large wet slab avalanches have been observed in the last couple of days. These avalanches are dense, destructive, and can run far, reaching otherwise snow-free valley bottoms.
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
