Avalanche Forecast

Issued: Apr 19th, 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.

chris gooliaff, Parks Canada

Glacier.

A super-early start is needed to beat the record heat. Evaluate the strength of the crust that you are traveling on. It will break down fast with the sun and warmth.

Summary

Weather Forecast

A record heat wave in Rogers Pass has brought clear skies, intense sun, and high freezing levels (3700m). Freezing levels remain high for the next few days, with very little recovery overnight. Winds will remain light at all elevations for the next 3 days. No precipitation in the forecast, except for isolated showers on Thursday.

Snowpack Summary

The melt-freeze crust at tree-line and alpine elevations is thinner and weaker with the warm overnight temp's. This will break down rapidly with the record heat wave. Below tree-line, the snowpack is isothermal and loses all strength with the daytime warming. Northerly aspects above 2300m still have dry snow.

Avalanche Summary

One wet size 2 slab was observed yesterday off of Tupper. Otherwise there has been little avalanche activity lately due to good overnight freezes of the snowpack. This will change with the forecast high freezing levels. Expect glide-cracks to become more active, which are opening up on many slopes and can fail unpredictably.

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 mtn. When the crust has completely 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

Possible - Likely

Expected Size

2 - 3

Cornices

Cornices have been shrinking with latest heat, but they are also 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 20th, 2016 8:00AM