Avalanche Forecast
Issued: Mar 2nd, 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.
swerner,
Avalanche Canada
More snow and a strong southwest wind continues to build touchy storm slabs. Its a good time to sit out the storm and avoid avalanche terrain. Storm slabs have the potential to step-down to deeper persistent weak layers, triggering large avalanches.
Summary
Confidence
Weather Forecast
Tuesday Night: Snow 5-10 cm. Ridgetop wind light from the South. Freezing levels in the valley bottom.
Wednesday: Snow 15-25 cm. Ridgetop wind moderate from the southwest. Alpine temperatures -2 and freezing levels 700 m.
Thursday: Mixed rain and snow, snow 10-20 cm. Ridgetop wind light from the southeast. Alpine temperatures near 0 and freezing levels 1100 m.
Friday: A mix of sun and cloud. Ridgetop wind from the South. Alpine temperatures near -5 and freezing levels valley bottom.
Avalanche Summary
On Tuesday, explosive control up to size 2 was reported in the recent storm snow.
Over the weekend a widespread natural avalanche cycle occurred up to size 3 and explosive control initiated numerous size 2-3 storm slabs and persistent slabs.
The storm continues and natural avalanche activity will likely occur through the forecast period.
It's a good time to stay very conservative, stick to simple terrain, and be aware of overhead hazards like large avalanche paths and cornices.
Snowpack Summary
60-80 cm of recent storm snow blanketed the region over the past few days. This was accompanied by strong to extreme southwest winds building deeper wind slabs on leeward slopes. Below 1000 m new snow is landing on a crust that formed during last weekend's storm. Massive cornices exist on ridgelines at treeline and in the alpine.
Snowfall accumulation now brings 90-250 cm over the plethora of old snow surfaces buried mid-February and deeper down buried late January. These old persistent weak layers comprise of hard wind-packed snow, feathery surface hoar crystals especially in areas sheltered from the wind, and sugary faceted snow that developed during the cold snap. These weak layers have been the result of several larger avalanches in the past week.
The mid-pack has been reported as being well-settled. There are presently no deeper concerns.
Terrain and Travel
- Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
- Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
- Use conservative route selection. Choose simple, low-angle, well-supported terrain with no overhead hazard.
- The more the snow feels like a slurpy, the more likely loose wet avalanches will become.
Problems
Storm Slabs
Recent storm snow accumulations are up to 80 cm in some parts of the region. It will continue to snow over the next two days building reactive storm slabs through the forecast period. Strong southwest wind persists, so wind slabs will rapidly build at upper elevations.
Large looming cornices exist along ridgelines, they may weaken with the warm-up on Thursday.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
The persistent slab has been reactive to rider and explosive triggering over the past week. There is anywhere from 90 to 250 cm of snow above a mixed bag of old snow surfaces buried in mid-February. The concern now is for storm slab avalanches stepping down to this deep layer and skier or rider triggering which would result in a very-large, consequential avalanche.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Loose Wet
Wet loose avalanches may occur at lower elevations depending on freezing levels. Obvious signs are natural avalanches, snowballing, moist and sticky snow surfaces.
Aspects: All aspects.
Elevations: Below Treeline.
Likelihood
Expected Size
Valid until: Mar 3rd, 2021 4:00PM
