Avalanche Forecast
Issued: Feb 24th, 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
Danger will increase as the day progresses with new snowfall and strong wind. Storm slabs, wind slabs, and a buried weak layer could be triggered by riders on Thursday.
Summary
Confidence
Moderate - Uncertainty is due to the limited number of field observations.
Weather Forecast
WEDNESDAY NIGHT: Increasing clouds, 30 to 60 km/h southwest wind, alpine temperature -12 C.
THURSDAY: Cloudy with snowfall, accumulation 5 to 10 cm, 30 to 60 km/h southwest wind, alpine temperature -10 C.
FRIDAY: Cloudy with snowfall, accumulation 5 to 10 cm, 20 to 40 km/h west wind, alpine temperature -10 C.
SATURDAY: Partly cloudy, 30 km/h west wind, alpine temperature -11 C.
Avalanche Summary
We received a few reports of storm slab avalanches around 30 cm deep on Monday and Tuesday, localized in the south of the region. The MIN here describes natural activity within the storm snow from earlier this week.
Looking towards Thursday, human triggering of storm, wind, and persistent slabs will remain likely. Conditions are not easily managed right now, warranting a conservative mindset!
Snowpack Summary
Stormy conditions will impact the region on Thursday, building on slabs formed earlier this week. Wind slabs are expected to build over the day in exposed terrain at treeline and alpine elevations. Storm slabs may build in sheltered areas at all elevations. These slabs are expected to reach between 20 and 50 cm thick over the region and sit above sugary faceted snow formed mid-February.
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
- Watch for changing conditions today, storm slabs may become increasingly reactive.
- 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
Stormy conditions will bring new snow and strong wind to the region. This snow will build on slabs formed earlier this week. These storm slabs are likely around 30 to 50 cm thick south of Crowsnest Pass and 20 to 30 cm thick elsewhere. The slabs sit on sugary faceted snow formed during the cold spell mid-February. Keep in mind that strong wind will also form wind slabs in exposed terrain at higher elevations.
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 25th, 2021 4:00PM
