Avalanche Forecast
Issued: Feb 1st, 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.
JSmith,
Avalanche Canada
Touchy storm slabs are sitting on a very weak layer of surface hoar which is very likely to be reactive to human triggers, even in low angle terrain. Avalanches may be larger than expected due to the presence of this weak layer.
Summary
Confidence
Weather Forecast
MONDAY NIGHT: Snow; 15-20 cm. / Strong, south ridgetop wind / alpine low temperature -7 / Freezing level 600 m.
TUESDAY: Cloudy with flurries; 0-3 cm. / Moderate, southwest ridgetop wind / alpine high temperature -4 / Freezing level 700 m.
WEDNESDAY: Mostly cloudy with sunny periods / Light, northwest ridgetop wind / alpine high temperature -8 / Freezing level valley bottom.
THURSDAY: Cloudy with flurries; 3-5 cm. / Moderate, west ridgetop wind / alpine high temperature -9 / Freezing level valley bottom.
Avalanche Summary
A widespread natural cycle and numerous skier triggered storm slab avalanches up size 2 were reported on all aspects in the Gorge area west of Revelstoke on Sunday. These storm slab avalanches were running on a weak layer of surface hoar that was buried by the recent storm. See one of numerous MIN reports Here.
Touchy storm slabs are sitting on a very weak layer of surface hoar which is very likely to be reactive to human triggers, even in low angle terrain. Avalanches may be larger than expected due to the presence of this weak layer.
Snowpack Summary
25-30 cm of new snow as of Monday afternoon brings recent snow totals up to 45 cm. Rising freezing levels throughout the storm has caused rapid slab formation. These touchy storm slabs are sitting on multiple weak layers of surface hoar. The first being below the most recent snow, and the second down 50-60 cm.
Observers continue to find a third layer of surface hoar from earlier in January down 70-100 cm. in sheltered, open areas near treeline.
The mid and lower snowpack is generally well settled and strong.
Terrain and Travel
- Keep in mind that human triggering potential persists as natural avalanching tapers off.
- Be aware of the potential for large avalanches due to the presence of buried surface hoar.
- Use conservative route selection. Choose simple, low-angle, well-supported terrain with no overhead hazard.
- Avoid exposure to overhead avalanche terrain, avalanches may run surprisingly far.
- Be aware of the potential for human triggerable storm slabs at lower elevations, even on small features.
Problems
Storm Slabs
Touchy storm slabs are sitting on a very weak layer of surface hoar which is very likely to be reactive to human triggers, even in low angle terrain. Avalanches may be larger than expected due to the presence of this weak layer.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
New snow loads have potential to awaken deeply buried weak layers.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Valid until: Feb 2nd, 2021 4:00PM
