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, 2021–Mar 1st, 2021

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

Banff Yoho Kootenay.

Strong to Extreme winds and more snow will continue to develop new wind slab at upper elevations. This new load overlays a weak faceted snowpack in many areas.

Weather Forecast

Strong to extreme Westerly winds at mountain top will begin to dissipated late Tuesday. A short pulse of precipitation is forecasted late Monday, with accumulation amounts of 5-20cm of snow. Freezing levels with remain at valley bottom with temperatures ranging from -5 to -10.

Snowpack Summary

15 to 30cm of storm snow since Friday. Snow and wind have created wind slabs in alpine lee areas and exposed tree line slopes. In thin snowpack areas 30-60 cm of snow sits over weak facet interfaces and facet sun crust interfaces on southerly aspects. In deeper snowpack areas there was less facetting, and the recent storm snow is bonding better.

Avalanche Summary

Saturday we received a report of a skier accidental size 2.5 that released out of a southerly aspects at tree line on Simpson Ridge. A fracture line profile today revealed that this avalanche failed on a weak facet interface 40-80cm down. Other reports and observations have indicated an increase in avalanche activity on this persistent weak layer.

Confidence

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.

Loose Dry

Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.

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.