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 21st, 2023–Feb 22nd, 2023

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

North Rockies, Kakwa, McGregor, Pine Pass, Tumbler.

Wind slabs are found on atypical south to west slopes due to strong northeast wind. The consequence of being caught in an avalanche is even higher during cold weather.

Confidence

Moderate

Avalanche Summary

Numerous small to large (size 1 to 2) storm and wind slab avalanches were observed, likely releasing within the past few days.

Looking forward, we anticipate that the northeast wind is forming wind slabs that could be triggered by riders on south to west slopes. These slopes are atypical for a wind slab problem so use caution when in wind exposed terrain.

Snowpack Summary

Strong northeast wind is redistributing the 40 to 80 cm of recent storm snow into wind slabs on southerly slopes. Very cold weather may allow for these slabs to linger for longer than is typical.

The mid-pack is gaining strength and consists of rounding facets and decomposing melt-freeze crusts.

A weak layer of large and weak facets is found near the base of the snowpack. The latest observed avalanche was in early February. Although the likelihood of triggering this layer is low, the consequence of doing so would be high. This layer is most likely to be human-triggered in thin, rocky slopes at alpine and upper treeline elevations.

Weather Summary

Tuesday Night

Clear skies with no precipitation, 40 km/h northeast wind, treeline temperature -27 °C.

Wednesday

Clear skies with no precipitation, 40 km/h northeast wind, treeline temperature -29 °C.

Thursday

Partly cloudy with no precipitation, 50 km/h northeast wind, treeline temperature -30 °C.

Friday

Increasing clouds with afternoon snowfall, trace accumulation, 50 km/h west wind, treeline temperature - 20 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Expect slab conditions to change drastically as you move into wind exposed terrain.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.

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.

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.