Avalanche Forecast

Issued: Apr 25th, 2023 4:00PM

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

Avalanche Canada CG, Avalanche Canada

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Rain up to Treeline elevations is forecasted for Rogers Pass. With its arrival expect avalanches to increase in size/frequency throughout the park.

Summary

Confidence

Moderate

Avalanche Summary

Numerous moist/wet, loose surface avalanches have been observed from steep gullies/slopes on all aspects at and below treeline. These point releases gather substantial mass as they move downslope into warmer snow.

As the week continues to warm up, expect these wet/loose avalanches to increase in size and potentially step down to deep layers, possibly even the Nov 17 facets.

Snowpack Summary

At Treeline elevations and below, rain and clouds are preventing a strong surface crust recovery.

In the high Alpine, true N'ly aspects hold dry snow. On solar aspects, a breakable crust overlies a series of buried crusts, which may provide a failure plane for slab avalanches as temps rise.

The Nov 17 basal weakness can still be found in many areas, ~20-40cm above the ground.

Weather Summary

A warm, wet Wed, then clearing and much warmer conditions arriving for the weekend.

Tonight: cloud/clear periods, Alp low -2*C, gusty mod/strong SW winds, 1800m FZL

Wed: Rain, flurries (10cm) above 2200m, Alp high 2*C, strong SW winds

Thurs: sun and cloud, Alp high 2*C, light/mod W winds, 2400m FZL

Fri: sun, Alp high 8*C, 3600m FZL

Terrain and Travel Advice

  • If triggered loose wet avalanches may step down to deeper layers resulting in larger avalanches.
  • The more the snowpack warms-up and weakens, the more conservative you`ll want to be with your terrain selection.
  • Avoid terrain traps such as gullies and cliffs where the consequence of any avalanche could be serious.

Problems

Loose Wet

An icon showing Loose Wet

The Spring snowpack relies on cold, clear nights to re-form a strong, supportive surface crust. Without overnight recovery, loose/wet avalanches are likely from steep terrain, especially with the added input of sun or rain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs

Up to 60cm of settled snow covers a series of crusts combined with surface hoar/facets in some locations. Loose wet avalanches in motion have the potential to step down to these layers, creating large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1.5 - 3

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

The increasing warmth and rain is beginning to percolate deeper into the snowpack. The potential for this early season basal weakness to wake up increases with these two added inputs.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 4.5

Valid until: Apr 26th, 2023 4:00PM