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

Feb 28th, 2024–Feb 29th, 2024

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

Regions

Purcells, Dogtooth, East Purcell.

Avoid avalanche terrain.

We are expecting widespread, large natural avalanche activity.

Stick to low angle terrain with no overhead hazard.

Confidence

High

Avalanche Summary

Numerous natural, skier, and explosive-triggered avalanches up to size 3 have been reported in the past few days throughout the region. All avalanches slid on layers in the upper snowpack, up to 70 cm deep.

We expect avalanche activity to increase in size and frequency on Thursday.

Snowpack Summary

Up to 30 cm of new snow will have fallen by mid day on Thursday. This new snow will likely form touchy storm slabs.

A layer of facets, surface hoar and a crust is down up to 50 cm.

A widespread crust formed in early February is buried roughly 40 to 80 cm and extends up to 2400 m. Facets have been found above this crust. This layer has produced many concerning avalanches across the province.

The mid and lower snowpack is largely faceted with depth hoar and a crust found at the bottom of the snowpack in many areas.

Weather Summary

Wednesday Night

Cloudy with up to 20 cm of new snow. 30 to 50 km/h south alpine wind. Treeline temperature -4°C.

Thursday

Mostly cloudy with up to 10 cm of new snow. 20 to 40 km/h southwest alpine wind. Treeline temperature -5°C.

Friday

A mix of sun and cloud with trace amounts of new snow. 10 to 20 km/h southeast alpine wind. Treeline temperature -7°C.

Saturday

A mix of sun and cloud with trace amounts of new snow. 10 to 30 km/h southeast alpine wind. Treeline temperature -9°C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Be aware of the potential for large, destructive avalanches due to the presence of deeply buried weak layers.
  • Remote triggering is a concern, avoid terrain where triggering slopes from below is possible
  • Make conservative terrain choices and avoid overhead hazard.

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.

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.