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

Jan 31st, 2015–Feb 1st, 2015

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

Regions

South Rockies.

Lingering deep persistent weaknesses remain a concern in isolated areas. Check out the new blog video from our field team at http://www.avalanche.ca/blog for the latest update on local conditions.

Confidence

Good - Due to the quality of field observations

Weather Forecast

Tonight we should see relatively calm and cold conditions during a break between systems. Sunday should remain overcast with the possibility of light accumulations up to 2cm. Monday we may see a another system bring 2-5cm of snow and a high of -2 at treeline, with freezing levels likely staying close to valley bottoms. Tuesday will be similar to Monday with slightly warmer temperatures and similar precipitation amounts.

Avalanche Summary

No new avalanches have been reported. On Wednesday a size 2 avalanche was accidentally triggered on an east aspect in the alpine by a sledder near Racehorse Pass (Crowsnest) on the December persistent weak layer.

Snowpack Summary

Recent sunny weather and high freezing levels have decimated the lower elevation snowpack. As a result the threshold for avalanches in most of the region has risen to approximately 1600m, potentially higher on solar aspects. 4-8cm of new snow has covered up a melt freeze crust and/or surface hoar, or a combo of both. The melt freeze crust exists up to approximately 1900m and up to all elevations on solar aspects. Time will tell, but I suspect this new layer will likely cause problems down the line and is a good one to keep in mind as it becomes buried deeper over time. The mid-December crust/facet/surface hoar layer is down 40-85cm and is suspected to be reactive in isolated areas, especially where a slab of stiffer snow has consolidated above it. This layer has proven easier to trigger from shallow and rocky areas in the alpine and treeline.

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.