Avalanche Forecast
Issued: Feb 21st, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs, Persistent Slabs and Loose Wet.
mconlan,
Avalanche Canada
A storm will impact the region Sunday night into Monday, forming new slabs, destabilizing the snowpack, and increasing the likelihood of triggering buried weak layers. An avalanche cycle may occur at all elevation bands. Travel in avalanche terrain is not recommended.
Summary
Confidence
Moderate - Uncertainty is due to the track & intensity of the incoming weather system.
Weather Forecast
SUNDAY NIGHT: Cloudy with snowfall, accumulation 5 to 15 cm, 50 gusting to 100 km/h southwest wind, alpine temperature -6 C, freezing level 1300 m.
MONDAY: Cloudy with snowfall, accumulation 10 to 20 cm and local enhancements possible, 40 to 80 km/h southwest wind, alpine temperature -5 C, freezing level 1500 m.
TUESDAY: Cloudy with snowfall and afternoon clearing, accumulation 5 to 15 cm, 30 km/h west wind, alpine temperature -8 C.
WEDNESDAY: Clear skies, 20 km/h southwest wind, alpine temperature -10 C.
Avalanche Summary
Many small to large (size 1 to 2) wind slab avalanches have been triggered within the past week, such as this one.
Looking forward, new storm and wind slabs will form and likely be reactive to human traffic. Natural avalanche activity may occur, so best to stay well away from concerning avalanche terrain on Monday.
Snowpack Summary
New snow and strong wind will form new storm and wind slabs Sunday night into Monday above around 1500 m. Below, rain will soak the snow surface. The snow will overly hard wind affected surfaces in exposed terrain and sugary faceted grains in sheltered terrain. Ultimately, this new snow may not bond well to previous surfaces and increase the likelihood of avalanche activity.
Around 50 to 80 cm deep, a weak layer of surface hoar may be found in sheltered terrain or otherwise faceted grains and/or a hard melt-freeze crust.
Weak faceted grains and a decomposing melt-freeze crust are likely found near the base of the snowpack. There have not been recent avalanche observations on this layer, but steep and rocky slopes as well as shallow snowpack areas should be approached with caution.
Terrain and Travel
- Avoid all avalanche terrain during periods of heavy loading from new snow and wind.
- Travel in alpine terrain is not recommended.
- Be aware of the potential for large avalanches due to the presence of buried surface hoar.
Problems
Storm Slabs
20 to 40 cm of snow and strong southwest wind are forecast above around 1500 m, which will form new storm slabs in sheltered areas and wind slabs in exposed terrain. Best to avoid avalanche terrain if you find 25+ cm of snow accumulation, as an avalanche cycle may occur.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Around 50 to 80 cm of snow overlies a buried weak layer of surface hoar, faceted grains, and/or a melt-freeze crust, depending on elevation and aspect. Reports to date suggest the Elk Valley being the most problematic area, but don't let your guard down elsewhere. Avalanches have occurred on surprisingly shallow slope angles and they can easily be remotely triggered.
Aspects: All aspects.
Elevations: Treeline.
Likelihood
Expected Size
Loose Wet
Rain below the snow-rain line will rapidly destabilize the snowpack and promote wet loose avalanche activity.
Aspects: All aspects.
Elevations: Below Treeline.
Likelihood
Expected Size
Valid until: Feb 22nd, 2021 4:00PM
