Avalanche Forecast
Issued: Feb 11th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
trettie,
Avalanche Canada
Avoid avalanche terrain. New touchy storm and wind slabs will form throughout the day.
Summary
Confidence
Avalanche Summary
On Thursday the fresh snow was reactive to skiers, with sluffing, natural storm slab avalanches to size 2.5, and wind slabs to size 1.5 reactive to skiers. With more snow in the forecast, expect the snowpack to continue to be reactive to skier- and rider-traffic.
On Wednesday, skiers triggered a large, size 2, avalanche near Ningunsaw. The Deep Persistent avalanche was triggered on an east aspect near ridgetop in a thin, rocky start zone and failed on basal facets.
Snowpack Summary
40-70 cm of recent storm snow overlies older wind-affected surfaces and a supportive melt-freeze crust up to 1800 m and steep solar slopes. South-southwesterly winds have been scouring and pressing southerly slopes and wind slabs on northerly aspects. Large cornices are also being reported on many northerly aspects.
80 to 200cm of storm snow from the past two weeks is settling over a layer of facets, crust, and previous wind-affected surfaces in alpine terrain. We're continuing to track this layer given recent avalanches on this interface under the patterns of continuous loading and successive natural avalanche cycles.
The mid and lower snowpack continues to bond and stabilize while a number of buried weak layers are still being tracked by professionals in the region, having produced a few large avalanches in the not-too-distant past.
Weather Summary
Saturday Night
Stormy with 5 to 30cm of new snow expected. Moderate to strong southwest winds and a low of -4 at 1500m.
Sunday
Stormy with 15 to 50cm of new snow expected. Strong southwest winds and a high of -3 at 1500m.
Monday
Cloudy with 5 to 15cm of new snow expected. Moderate westerly winds and temperatures at 1500m falling throughout the day to -8.
Tuesday
A mix of sun and cloud with the possibility of light flurries bringing trace amounts of new snow. Light southwest winds and a high of -10 at 1500m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Avoid all avalanche terrain during periods of heavy snowfall.
- Storm slab size and sensitivity to triggering will likely increase through the day.
- Use conservative route selection. Choose simple, low-angle, well-supported terrain with no overhead hazard.
- Avoid exposure to slopes that have cornices overhead.
Problems
Storm Slabs
New snow and strong southwest winds will form touchy storm and wind slabs. The largest and most reactive slabs will be found on north and east aspects.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
A deeply buried weak layer still presents a Low Probability/High Consequence situation. New snow and wind has been testing this weakness in the snowpack and the results still aren't in. This layer would be most likely to be triggered in places where the snowpack is shallow and rocky.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 12th, 2023 4:00PM
