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
New snow and strong southerly winds will form fresh storm slabs reactive to human triggers. Conservative terrain choices will be CRITICAL to playing safe today.
Summary
Confidence
Weather Forecast
MONDAY NIGHT: Snow; 5-15 cm. / Strong, south ridgetop wind / alpine low temperature -5 / Freezing level 1400 m.
TUESDAY: Snow; 5-15 cm. / Moderate, southwest ridgetop wind / alpine high temperature -4 / Freezing level 1500 m.
WEDNESDAY: Mostly cloudy with sunny periods / Light, northwest ridgetop wind / alpine high temperature -7 / Freezing level valley bottom.
THURSDAY: Cloudy / Moderate, northwest ridgetop wind / alpine high temperature -8 / Freezing level valley bottom.
Avalanche Summary
Small but touchy storm slabs propagating across entire features were reported near Golden on Sunday.
Check out this MIN on the 29th and this MIN on the 28th from near Kicking Horse.
We're continuing to track a layer of surface hoar from early January which was reactive in previous weeks. Refer to: MIN report 1 & MIN report 2 from Hope Creek on the 20th.
Snowpack Summary
25-45 cm of forecast and recent snow will have accumulated by Monday afternoon. This recent snow arrived with light to moderate wind, warm temperatures and will have numerous storm interfaces, including another layer of surface hoar from Saturday that may serve as failure planes. Check out this MIN and this MIN from the south Purcells. All this recent snow sits on top of a known weak layer of widespread surface hoar, facets, sun crust and old wind surfaces from the last drought.
Buried 50-90 cm is an older surface hoar and / or a thin melt crust from Jan 11th. This layer was more prominent in the north Purcells in sheltered, open slopes at treeline and may become reactive with incoming warm temperatures and snow.
Two deeper layers persist, though they have been recently unreactive. Down 100-150 cm lies the December weak surface hoar / crust / facet layers. Closer to the ground lies the early November crust facet complex. Though unlikely to trigger, caution for these layers remains with large loads in steep, shallow, rocky areas with a thin to thick snowpack or shallow areas below treeline.
Terrain and Travel
- Be aware of the potential for larger than expected storm slabs due to the presence of buried surface hoar.
- In times of uncertainty conservative terrain choices are our best defense.
- Use increased caution at all elevations. Storm snow is forming touchy slabs.
- Be aware of the potential for large avalanches due to the presence of buried surface hoar.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Problems
Storm Slabs
25-35 cm of recent snow has formed reactive storm slabs sitting on a weak layer of surface hoar. These slabs may be especially reactive in wind affected terrain.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
A weak layer of surface hoar buried Jan 11 is down 40-120 cm and may be found on sheltered slopes near treeline in northern parts of the region. Deeper layers from early December and November can still be found in the snowpack. These layers may become reactive with a large load or in shallow, rocky or thin to thick snowpacks.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 2nd, 2021 4:00PM
