Avalanche Forecast

Issued: Nov 29th, 2021 3:00PM

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

Avalanche Canada JMackenzie, Avalanche Canada

While natural avalanche activity has tapered a bit, wind slab conditions are prime for human triggering at upper elevations. Avoid avalanche terrain. We are at the upper level of "Considerable" hazard.

Summary

Confidence

Moderate -

Weather Forecast

Tuesday will be a mix of sun and cloud with light flurries. Accumulations are likely to be less than 5cm. Freezing levels should hold steady at about 1700m with daytime highs near -4 in the Spray Valley. Winds will be in the moderate to strong range from the SW. Another storm is expected Wednesday with up to 25cm and 150km/h winds!

Avalanche Summary

A few naturally triggered slab avalanches up to size 2 were observed today, mainly in Alpine terrain. This adds to the numerous avalanches observed yesterday up to size 3 that had run well into their historic paths.

Snowpack Summary

24 hour snowfall amounts are difficult to quantify as the recent storm came as rain and snow. At Highwood Pass today ski pen was 30 to 40cm in thick cakey snow. Winds have remained strong for many days, which has contributed to widespread wind slab development in the Alpine and open areas at Treeline. These fresh slabs seem prime for human triggering. At lower elevations, below approximately 2000m, there is a skiff of snow over a freshly formed rain crust.

Terrain and Travel

  • Avoid freshly wind loaded terrain features.
  • Approach lee and cross-loaded slopes with caution.
  • Avoid areas with a thin or variable snowpack.
  • Ice climbers should be equipped with avalanche safety gear.

Problems

Wind Slabs

An icon showing Wind Slabs

Extensive wind slab development has occurred in the Alpine and open areas at Treeline. These slabs appear prime for human-triggering. It will take several days for these slabs to stabilize

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

1.5 - 3

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

This layer was overloaded today and reacted accordingly. We are thinking it will take a few days and cooler temperatures to for it to adjust. These avalanches could be very large.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

2 - 3

Valid until: Nov 30th, 2021 3:00PM