Avalanche Forecast
Issued: Jan 31st, 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.
kdevine,
Avalanche Canada
Continued stormy weather is keeping danger elevated as more snow adds load to a buried weak layer. Stick to simple terrain with no overhead hazard.
Summary
Confidence
Moderate - Forecast snowfall amounts are uncertain.
Weather Forecast
SUNDAY NIGHT - Flurries, 10-15 cm / strong southwest wind / alpine low temperature near -5 / freezing level 1500 m
MONDAY - Flurries, 10-15 cm with another 15-20 cm overnight / moderate to strong southwest wind / alpine high temperature near -4 / freezing level 1500 m
TUESDAY - Flurries, 5 cm / moderate to strong southwest wind / alpine high temperature near -7 / freezing level 1500 m and dropping to valley bottom overnight
WEDNESDAY - Mainly cloudy / light west wind / alpine high temperature near -10
Avalanche Summary
Natural and human triggered avalanches are expected to be likely on Monday with continued stormy weather creating reactive storm slabs.
On Thursday and Friday, there were numerous reports of size 1-2 human triggered storm slab avalanches. The primary failure plan in these avalanches was the latest weak layer of surface hoar from late January that was 20-40 cm deep at the time.
Snowpack Summary
Fresh snow accumulations between Sunday night and Monday afternoon are expected to be around 20-30 cm. There is now about 60-80 cm of total recent storm snow sitting above a melt-freeze crust in many areas around treeline and below treeline, on a sun crust on steep south-facing slopes, and on large surface hoar in sheltered areas.
There are potentially several more layers of surface hoar in the upper snowpack, with the most notable one down about 60-120 cm. This layer was buried in early January.Â
A couple of crusts surrounded by weak faceted grains are buried deep within the snowpack. The upper layer is 100 to 150 cm deep and the lower one is near the ground.Â
Terrain and Travel
- Use conservative route selection. Choose simple, low-angle, well-supported terrain with no overhead hazard.
- Avoid all avalanche terrain during periods of heavy loading from new snow and wind.
- Be aware of the potential for large avalanches due to the presence of buried surface hoar.
Problems
Storm Slabs
Storm slabs will be building throughout the day on Monday, becoming increasingly reactive as more snow accumulates. This adds to slabs from last week's storm that have been teetering on a fragile layer of surface hoar. Natural avalanches will be likely at higher elevations on wind loaded slopes, while human triggering is a serious concern at all elevations.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
A deeper weak layer of surface hoar that was buried in early January may become reactive as loading from snow and wind continues.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Valid until: Feb 1st, 2021 4:00PM
