Avalanche Forecast

Issued: Apr 21st, 2016 8:00AM

The alpine rating is below threshold, the treeline rating is below threshold, and the below treeline rating is below threshold. Known problems include Loose Wet, Wet Slabs and Cornices.

andrew jones, Parks Canada

Glacier.

Rain will destabilize the already moist snowpack. Expect conditions to deteriorate quickly this afternoon.

Summary

Weather Forecast

Expect a mix of sun and cloud with isolated showers today. Alpine temperatures reach a high of 16 this afternoon with freezing levels reaching 3600m. Winds will be moderate from the south. A frontal system moves in early tomorrow morning with rain continuing through the weekend. Freezing levels will remain high.

Snowpack Summary

Sustained warm temperatures have led to poor overnight recovery of the snowpack with moist isothermal snow in the top 1m. Surface crusts break down well before noon on all aspects at treeline and lower alpine. Snow is disappearing rapidly from lower elevations.

Avalanche Summary

Natural avalanche cycles continue to occur with daytime warming with large loose wet avalanches running to valley bottom.

Confidence

Problems

Loose Wet

Warmer temp's are preventing a strong surface crust to refreeze at night. This crust is holding everything together on the mountain. When the crust has broken down, loose wet avalanches will be easy to trigger and can entrain significant mass.

Use extra caution on slopes if the snow is moist or wet.Start and finish early before the surface crusts melt.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Wet Slabs

With the warms temps & strong solar radiation, avalanche activity will surely increase. Without a strong overnight freeze the snowpack will warm & lose its structure. As this happens it will sporadically fail as large destructive wet slab avalanches

Use extra caution on solar slopes, or if the snow is moist or wet.Avoid exposure to overhead slopes with Glide Cracks. Avalanches may reach the end of run out zones.

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

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 3

Cornices

Cornices are sagging and are precariously perched on high alpine ridges. Sun and continued warmth will further weaken them.

Cornices become weak with daytime heating, so travel early on exposed slopes.Give cornices a wide berth when travelling on or below ridges.

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Apr 22nd, 2016 8:00AM