Dashboard Regions Weather Stations Radar Alerts Glossary
Contact About
Log In

Register for an account and never miss a forecast again!

Register

Avalanche Forecast

Archived

Nov 22nd, 2024–Nov 23rd, 2024

Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches unlikely.
Below Treeline
Below Threshold.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches unlikely.
Below Treeline
Below Threshold.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely.
Below Treeline
Below Threshold.

Regions

Banff Yoho Kootenay, Little Yoho, Banff, East Side 93N, Kootenay, Lake Louise, LLSA, Sunshine, West Side 93N, Field.

Recent snowfall has enhanced skiing conditions at higher elevations, but be mindful of rocks and hidden hazards.

As new snow amounts increase, the October 23 weak layer is slowly becoming more reactive.

Watch locally for increased winds. It won't take much for the new snow to start sloughing.

Confidence

Moderate

Avalanche Summary

During avalanche control in Delerium Dive, Sunshine Ski Hill had numerous results failing on the October crust. A small hand charge triggered a size 2.5, a skier triggered a size 2, and numerous other smaller results. Lake Louise also had another size 2 explosive-controlled slide on the October crust in Whitehorn which is a recurring theme this past week.

Snowpack Summary

10-30 cm of low-density storm snow sits over an early-season snowpack ranging from 50-90 cm at TL. Two weak layers exist: a Nov 9 crust/surface hoar 25-40 cm above the ground and an Oct crust/facet layer right above the ground. We have limited observations of how widespread this layer is, but we think the Oct crust is more prominent at treeline and above on Northerly aspects.

Weather Summary

Two small back-to-back storms are forecasted from Friday night into Saturday. They will begin as upslope storms and transition to the southwest, with 5-10 cm of snowfall expected. Winds will be light throughout the weekend, and temperatures will be -8 to -10C.

Terrain and Travel Advice

  • Be aware of the possibility for full depth avalanches due to deeply buried weak layers.

Problems

Deep Persistent Slabs

Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.