Wind Slabs
N
NE
E
SE
S
SW
W
NW
- Alta montaña
- Límite del bosque
- Bajo el límite del bosque
- Probabilidad
- Possible
- Tamaño
- 1–2
Previous southwest winds have formed wind slabs in lee terrain features at higher elevations.
Boletín de aludes
Ver en el mapaSouth Coast Inland
Nov 29 – 30, 2020Avalanche Canada
Archivado · caducó 6 years ago
Peligro de aludes
Tue
Wed
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
1 · Débil
Lo esencial
Wind slabs at upper elevations may remain sensitive to human triggering Sunday. The next storm is forecast to trickle in late in the day.
Problemas de aludes
Deep Persistent Slabs
NNEESESSWWNW- Alta montaña
- Límite del bosque
- Bajo el límite del bosque
- Probabilidad
- Possible
- Tamaño
- 1.5–2.5
In the north of the region (e.g., Duffey Lake), there is potential to trigger a weak layer of sugary faceted grains around a hard melt-freeze crust near the base of the snowpack. The last skier-triggered avalanche on this layer was last weekend. The most likely terrain features of concern are where the ground cover is smooth, such as on scree slopes, rock slabs, or glacial ice.
Confidence
Low - Uncertainty is due to the limited number of field observations. Recent weather patterns have resulted in a high degree of snowpack variability within the region.
Weather Forecast
Saturday night: Partly cloudy, moderate southwest wind, freezing level 500-800 m.
Sunday: Increasing cloud with wet flurries starting in the afternoon, moderate to strong southwest wind. Freezing level varies between models indicating a large near-freezing band 1000 to 1500 m in the north and encompassing valley bottom to mountaintop in the south.
Monday: 5-10 cm new snow, strong southwest wind, freezing level 1300 m.
Tuesday: Up to 10 cm new snow overnight then clearing, light southwest wind, freezing level 700 m.
Avalanche Summary
In the south, a skier accidental wind slab avalanche was reported on Friday in the Coquihalla area.
In the north, large (size 2) storm slab avalanches were triggered naturally and by explosives on Wednesday near Duffey Lake. They occurred on northerly aspects in alpine terrain. The most recent report of an avalanche on the early-November layer was from November 21 near Duffey Lake. Check out this MIN for a photo.
Our eyes and ears in the mountains are limited at this time of year and may continue this winter due to fewer professional observations. If you see anything (or don't) while out in the field, please consider sharing it with us and fellow recreationists via the Mountain Information Network (MIN). Photos are especially helpful! A big thank you to those that have already shared their observations thus far.
Snowpack Summary
Previous southwest winds have produced wind slabs in lee terrain features at higher elevations.
The lower snowpack is characterized by a few crusts formed during warm periods over the last month.
- In the north, treeline snowpack depth sits around 80 to 120 cm. The crust of note here is sitting near the base of the snowpack, likely surrounded by a weak layer of sugary facets. Snowpack tests and recent avalanche activity suggest that this layer could be triggered by humans and produce large avalanches.
- In the south of the region, the snow line has been reported around 700 m near Hope and treeline snowpack depth sits around 100-150 cm. The deeper crusts in this area are generally well bonded to surrounding snow.
Terrain and Travel
- Be careful as you transition into wind affected terrain.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Be cautious of buried obstacles especially below treeline.