Avalanche Forecast
Issued: Mar 11th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
wlewis,
Avalanche Canada
Plan your travels with aspect in mind.
Wind slabs remain possible to trigger on south and west facing slopes. Watch for clearing skies - short periods of sunshine can rapidly increase reactivity on south facing/sun affected slopes.
Summary
Confidence
Moderate
Avalanche Summary
Wind slabs have been naturally and human triggered to size 2 this week. Activity appears to be tapering and wind slabs are likely becoming more stubborn to human triggers with size 1 wind slabs reported on Friday. Wind slab activity has been limited to south and west facing slopes, loaded from outflow winds.
Small solar triggered avalanches have been observed over the last few days. Even small periods of sunshine can rapidly change avalanche danger. Several cornice falls were reported, entraining a mass of snow on the slope below, but not triggering a slab.
On Thursday, a large explosive charge produced a size 1.5 persistent slab avalanche on a buried weak layer. A size 2.5 naturally triggered slab avalanche was observed at 1750 m, which ran to valley bottom. This is believed to be up to several days old and the failure plane is unknown.
Snowpack Summary
Surface conditions are a mix of very wind affected snow in exposed terrain features, wind slabs, sun crusts on steep solar aspects, and preserved softer snow in sheltered areas.
A layer of small surface hoar or facets is now buried over 80 cm deep. A facet/crust layer formed in late January exists around 150 cm deep. Large avalanches were suspected to have run on this layer in mid February. Triggering these deeper layers may still be possible for large loads in places where the snowpack is shallow.
The lower snowpack is generally well consolidated but the snowpack becomes thinner and weaker near the ground as you move further inland.
Weather Summary
Saturday Night
Partly cloudy. Moderate southeasterly wind, with stronger winds channeled in the valleys. Freezing level below valley bottom.
Sunday
A mix of sun and cloud. Up to 5 cm of snowfall possible. Moderate southeasterly winds with stronger winds possibly channeled in the valleys. Alpine high -8 ËšC. Freezing level around 200 m.
Monday
A mix of sun and cloud. Light to moderate southwest wind. Alpine high -5 ËšC. Freezing levels below 500 m. Flurries may bring up to 2 cm of snow.
Tuesday
Mostly cloudy. Freezing levels rise to around 500 m, alpine high of -4 ËšC. Strong southwest winds. Flurries may bring up to 5 cm of snow.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
- Seek out sheltered terrain where new snow hasn't been wind-affected.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Problems
Wind Slabs
Wind slabs remain possible to trigger in terrain features that were reverse-loaded by consistent north/east winds. Wind slabs may sit over a sun crust on south facing slopes. Watch for wind drifted snow below ridge crests and rollovers and in cross-loaded terrain.
Look for signs of active wind transport, newer wind slabs are most reactive.
Aspects: South East, South, South West, West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 12th, 2023 5:00PM
