Avalanche Forecast

Issued: Apr 11th, 2019 5:32PM

The alpine rating is moderate, the treeline rating is low, and the below treeline rating is low. Known problems include Storm Slabs and Loose Wet.

jsmith, Avalanche Canada

Sea To Sky.

Recently formed storm slabs have been especially reactive to human triggers on northerly aspects below alpine ridgetops.

Summary

Confidence

High -

Weather Forecast

THURSDAY NIGHT: Cloudy / Light, northeasterly winds / Alpine low -3 C / Freezing level 1100 m.FRIDAY: Mix of sun and cloud / Light, westerly winds / Alpine high 1 C / Freezing level 1600 m.SATURDAY: Snow; 10-20 cm. / Moderate, southwesterly winds / Alpine high -2 C / Freezing level 1200 m.SUNDAY: Cloudy with isolated flurries; 0-3 cm. / Light, westerly winds / Alpine high -3 C / Freezing level 1000 m.

Avalanche Summary

On Wednesday, there were numerous small (size 1) skier triggered storm slabs reported on primarily northerly aspects below ridgetops near Whistler.On Monday, four skier-triggered storm slab avalanches (size 1.5-2) in the Whistler backcountry were reported on north facing aspects below alpine ridgetops, including this Decker Main MIN report here.

Snowpack Summary

Up to 20 cm. of recent storm snow is sitting on a melt/freeze crust, except for north facing terrain above 2000 m. where the old snow surface remained dry. This recent snow has been affected by the sun and re-distributed by southerly winds, forming wind slabs on lee features below ridgetops.The snowpack structure changes with elevation and aspect. Below roughly 1900 m. the snowpack is moist and is melting rapidly at lower elevations. Check out this useful link for managing avalanche hazard during spring conditions HERE.

Problems

Storm Slabs

Recent snowfall, wind and continued flurries have formed slabs around ridge crests and into the alpine. Use caution around cornices, lee features, and steep, convex slopes.

Give cornices a wide berth when travelling on or below ridges.Expect conditions to change rapidly with elevation.Be careful with wind-loaded pockets, especially near ridge crests and roll-overs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 1.5

Loose Wet

The recent snow will moisten quickly if the clouds clear or freezing levels rise. Loose wet avalanches can become dangerous quickly, so use added caution if the snow is moist or the sun comes out.

Use extra caution on slopes if the snow is moist or wet.Avoid sun-exposed slopes and overhead exposure during periods of intense sun.Cornices become weak with daytime heating, so travel early on exposed slopes.

Aspects: East, South East, South, South West, West.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 1.5

Valid until: Apr 12th, 2019 2:00PM