Avalanche Forecast

Issued: Apr 24th, 2023 4:00PM

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

GL, Avalanche Canada

Jasper, Brazeau, Churchill, Cirrus-Wilson, Fryatt, Icefields, Maligne, Marmot, Miette Lake, Pyramid.

The trend for the next few days is less overnight freeze and increasing freezing levels raising the potential of increased reactivity. Your strategy is to start and end early, avoid cornices, and anticipate natural activity to escalate with full depth releases possible.

Summary

Confidence

Low

Avalanche Summary

Monday's Maligne and Icefield's patrols noted nothing new. There was an avalanche Fatality in Banff Park near Lake Louise Saturday from a deep large human triggered slide. Last week a few large cornice triggered avalanches were noted on Alpine East aspects.

Post avalanche observations to the MIN.

Snowpack Summary

A dusting of snow overnight rests on sun crusts on solar aspects and a melt-freeze crust below tree line. Old wind slabs are on exposed alpine terrain. A layer of sun crust or facets linger in the mid-pack. The main concern is the depth hoar and basal facets at the bottom causing our deep persistent slab problem.

Weather Summary

Parkers ridge weather on Monday night will be clear and -4 °C. Tuesday is sun, cloud, flurries, -2 °C, and 1900m freezing level. Wednesday's freezing level is forecast to increase to 2500m and Thursday's will be 3000m.

Terrain and Travel Advice

Cornices become weak with daytime heating.
In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
Avoid exposure to slopes that have cornices overhead.

Problems

Deep Persistent Slabs

The bottom of the snowpack is inherently weak with well-developed Facets and Depth Hoar. The next few days could see this problem moving into the reactive category with dramatically rising freezing levels.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 4

Cornices

Cornices are large and ominous. The rising freezing levels will weaken them. When they fall, they can trigger large avalanches or just be a hazard by their sheer mass.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

2 - 3

Loose Wet

This problem will be increasing in frequency the next few days as less overnight freeze occurs and rising daytime freezing levels.

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

Elevations: Treeline, Below Treeline.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Apr 25th, 2023 4:00PM