Avalanche Forecast

Issued: Apr 17th, 2023 4:00PM

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

Avalanche Canada JA, Avalanche Canada


A top up of snow and decent refreeze tonight will mean for good travel in the morning. Expect to find fresh windslab in exposed areas in the alpine and treeline. Pay attention to signs of instability, dig down and be patient for proper spring to arrive.




Avalanche Summary

Explosives control in a permanently closed area at Marmot Basin on Sunday reported triggering a size 2 persistent slab, stepping down to basal weaknesses.

MIN report from Sunday at Hilda observed whumpfing in multiple locations above treeline.

No recent reports of natural avalanche activity but still be vigilant and make careful assessments.

Don't forget to post avalanche observations to the MIN.

Snowpack Summary

Up to 5-10cm of new snow around the Icefields area sits on top of a variety of surfaces - crusts on solar aspects & BTL and old wind pressed/ slab on exposed northerly aspects.

The snowpack below 1800m is in a daily melt-freeze cycle. The mid-pack above this elevation consists of multiple layers of sun crusts or facets. Depth hoar and basal facets make up the base of the snowpack.

Weather Summary

Tuesday will be another day of clouds with some isolated flurries. Alpine temperatures are forecasted to be a high of -3 °C. Ridge winds will be from the southwest (10-25 km/h) and freezing level rising to 1800 metres during the day. Tuesday evening will see freezing levels drop back down to valley bottom.

Wednesday will see similar conditions of clouds and chance of isolated flurries and an alpine high of -4°C.

Terrain and Travel Advice

  • Keep in mind that human triggering potential persists as natural avalanching tapers off.
  • Stay off recently wind loaded slopes until they have had a chance to stabilize.
  • Remember that in the spring strong solar radiation and warm temperatures can weaken the snow in a matter of minutes.
  • In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.


Deep Persistent Slabs

An icon showing Deep Persistent Slabs

The bottom of the snowpack is inherently weak with well-developed Facets and Depth Hoar.

Aspects: All aspects.

Elevations: Alpine, Treeline.



Expected Size

2 - 3.5

Wind Slabs

An icon showing Wind Slabs

Up to 10cm of new snow has been redistributed by moderate to strong winds from the southwest, building new windslabs in the lees of ridgecrest and into open treeline features.

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

Elevations: Alpine, Treeline.



Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs

A cornucopia of persistent weak layers in the midpack can be found as facets on polar aspects and sun crusts on solar aspects.

Aspects: All aspects.

Elevations: Alpine, Treeline.



Expected Size

1.5 - 2.5

Valid until: Apr 18th, 2023 4:00PM