Avalanche Forecast

Issued: Apr 20th, 2021 4:00PM

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, Cornices and Persistent Slabs.

Ian Jackson,

Email

Good travel conditions exist right now with dry snow on high north aspects. Start and finish your trips early to take advantage of lower avalanche danger in the mornings

Summary

Weather Forecast

Wednesday looks like another beautiful day to be in the mountains. Clear skies, a good freeze and slightly warmer than Tuesday. Winds are forecast to increase to moderate from the NW throughout the day and bring some clouds by afternoon. Thursday and Friday are looking to be cool with light snow and light winds.

Snowpack Summary

Dry snow exists above 2200 m on north aspects, but has been cooked by the sun on solar aspects where multiple crusts exist in the snowpack. Persistent layers in the mid and lower snowpack were re-activated in a few instances during the heating last week producing large avalanches with large loads (cornice failures and explosives).

Avalanche Summary

Some loose wet activity was observed as the day warmed up, but overall, much less than during last weeks warmup.

Confidence

Problems

Loose Wet

An icon showing Loose Wet

Clear skies mean solar aspects will start sluffing as the day warms up. These will start small as just the new snow sluffs and gradually get bigger as the surface crusts break down.

  • Use extra caution on solar slopes or if the snow is moist or wet.
  • Travel early before the heat of the day.

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

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 1.5

Cornices

An icon showing Cornices

Cornices are unpredictable even to experienced forecasters. However, we do know that they are big right now and will fall off sometime before summer. Some cornices failures last week were enough to trigger the persistent weak layers.

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

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs

Cooler temperatures may decrease the likelihood of deeper layers in the mid to lower snowpack being triggered. If there is a poor freeze or one of the many large cornices fails, larger avalanches on these layers are still a possibility.

  • Pockets of persistent slabs linger on alpine lee features.
  • Pay attention to overhead hazards like cornices which could trigger persistent slabs.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely

Expected Size

2 - 3.5

Valid until: Apr 21st, 2021 4:00PM