Avalanche Forecast
Issued: Feb 22nd, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
mconlan,
Avalanche Canada
Recently formed slabs will likely remain triggerable to riders on Tuesday. Conservative terrain travel is recommended!
Summary
Confidence
Moderate - Uncertainty is due to the track & intensity of the incoming weather system.
Weather Forecast
MONDAY NIGHT: Cloudy with snowfall, accumulation 5 to 15 cm and local enhancements possible, 30 to 60 km/h southwest wind, alpine temperature -7 C, freezing level dropping to valley bottom.
TUESDAY: Mix of sun and cloud, 30 km/h west wind, alpine temperature -10 C.
WEDNESDAY: Clear skies, 20 km/h southwest wind, alpine temperature -10 C.
THURSDAY: Cloudy with snowfall, accumulation 5cm, 30 to 60 km/h southwest wind, alpine temperature -9 C.
Avalanche Summary
Much of the region wasn't visible on Sunday and Monday due to stormy conditions. Natural and human-triggered avalanches were probably during that period, particularly in the high-snowfall areas of the region. We may see the evidence of the activity as the skies clear on Tuesday.
Snowpack Summary
Anywhere from 5 to 40 cm of snow fell on Monday, with the most in the south and west of the region near the divide. Storm slabs likely developed rapidly for high snowfall areas and wind slabs formed everywhere with strong southerly wind. The freezing level hovered around 1500 m, soaking the snowpack below. More snow, strong west wind, and a dropping freezing level are forecast for Monday night, building these slabs into Tuesday. The snow overlies previously hardened snow from wind effect or sugary faceted grains in sheltered areas.
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. This layer has so far shown to be most problematic around the Elk Valley, but you may find it elsewhere.
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
- Choose conservative terrain and watch for clues of instability.
- Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
- Be aware of the potential for large avalanches due to the presence of buried surface hoar.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
Problems
Storm Slabs
Both storm and wind slabs remain likely to be triggered by riders on Tuesday. The thickest slabs are likely found at higher elevations as well as in the south and west of the region where the most snow fell. Conservative terrain travel is recommended until the snow has some time to bond to the snowpack.
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.
Aspects: All aspects.
Elevations: Treeline.
Likelihood
Expected Size
Valid until: Feb 23rd, 2021 4:00PM
