Avalanche Forecast
Issued: Mar 12th, 2024 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs, Storm Slabs and Loose Wet.
bchristie,
Avalanche Canada
Stick to mellow terrain, and avoid travelling in or under large, open slopes.
Rider or sun-triggered avalanches could become very large if they step down to a deeper weak layer.
Summary
Confidence
Avalanche Summary
On Monday, several small to large (up to size 2.5) natural and rider triggered wind and storm slab avalanches were reported at treeline and below. See photo for example.
Limited persistent slab activity has been reported since Thursday, however, avalanches within the last week have been large and destructive, running full path. The photos below show an explosive triggered avalanche near Nelson, and a rider triggered avalanche in the Bonningtons, both several days old.
Snowpack Summary
Storm totals are expected to reach 40-60 cm by Tuesday afternoon. Storms slabs are currently not bonding well with the old snow surface - a crust on sun affected slopes, surface hoar in sheltered terrain, and wind affected snow in exposed areas.
A widespread crust with weak facets above is buried 100-150 cm deep and remains a very concerning layer for human triggering. While reports suggest this layer is becoming harder to trigger, it has produced very large avalanche activity this week.
The snowpack below the crust is generally strong.
Weather Summary
Tuesday Night
Cloudy. 15-25 cm of snow expected, but only 5-10 in the northwest and southeast corners of the forecast area. Light to moderate southwest ridgetop wind. Freezing level around 1000 m, with treeline temperatures around -6 °C.
Wednesday
Mostly sunny. No new snow expected. Light northwest ridgetop wind. Freezing levels rise to 1700 m, with treeline temperatures around -3 °C.
Thursday
Sunny. No new snow expected. Light northwest ridgetop wind. Freezing levels rise to 2000 m, with treeline temperatures around 0 °C.
Friday
Sunny. No new snow expected. Light to moderate northwest ridgetop wind. Freezing levels rise to 3000 m, with treeline temperature around 5 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Dial back your terrain choices if you are seeing more than 20 cm of new snow.
- Avoid avalanche terrain during periods of strong sun.
- Be mindful that deep instabilities are still present and have produced recent large avalanches.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
Problems
Persistent Slabs
While uncertainty exists about the likelihood of triggering, storm snow will add load and may increase reactivity. Avoid areas where the snowpack thins, like steep, rocky start zones where weak layers are more easily triggered.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Storm Slabs
Storm snow is likely not bonding well with the old snow surface. Human triggered avalanches are likely. Use extra caution around ridgecrests, rolls, and on convex slopes.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Loose Wet
With lots of recent storm snow, and sun in the forecast, loose avalanches are likely where spring sun hits loose storm snow for the first time.
Aspects: South East, South, South West, West, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 13th, 2024 4:00PM
