Avalanche Forecast
Issued: Mar 17th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs.
shorton,
Avalanche Canada
Cautious route-finding is recommended right now due to uncertainty about buried weak layers, especially in the eastern parts of the region where there is potential for large avalanches.
Summary
Confidence
Moderate - Uncertainty is due to the complexity of the snowpack’s structure.
Weather Forecast
THURSDAY NIGHT: Cloudy with scattered flurries bringing up to 5 cm of new snow, light wind from the southwest, treeline temperatures drop to -5 with freezing level around 1200 m.
FRIDAY: Mostly cloudy with some light flurries bringing trace amounts of snow, moderate wind from the southwest, treeline temperatures around -3 C with freezing level around 1500 m.
SATURDAY: Mostly cloudy with flurries starting midday brining up to 5 cm of snow, moderate wind from the southwest, treeline temperatures around -3 C with freezing level around 1500 m.
SUNDAY: Flurries continue overnight with 5 to 10 cm of new snow by the morning then sunny breaks in the afternoon, light wind from the west, treeline temperatures around -5 C with freezing level around 1300 m.
Avalanche Summary
Avalanche activity has declined since a natural cycle occurred during Tuesday's storm. The cycle involved many large storm slab avalanche in the top 20 to 40 cm of snow (size 2). On Wednesday, activity was limited to a few natural slab and loose avalanches triggered by warming on south-facing slopes (size 1 to 2).
There have been some notable human-triggered avalanches north of Nelson the past few days in the South Columbia region (read more in this blog). These have been larger storm slabs above weak layers, and we are uncertain whether these are signs of a developing persistent slab avalanche problem that could begin impacting northern and eastern parts of the Kootenay Boundary region as well.
Snowpack Summary
30 to 50 cm of snow from the past week is settling, and there is uncertainty about how well it will bond to underlying layers. In the Selkirks, especially north of Nelson, it appears this snow could be bonding poorly to underlying crust and surface hoar layers. In the Monashees, it appears this snow has formed a stronger bond to underlying crusts. There are several other crust layers found 30 to 70 cm deep, and it appears the snow is mostly well bonded to these crusts.
Terrain and Travel
- Uncertainty is best managed through conservative terrain choices at this time.
- Approach steep, open and/or sparsely treed slopes cautiously.
- Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
- Investigate the bond of the recent snow before committing to your line.
Problems
Persistent Slabs
30 to 50 cm of recent snow has potential to form a persistent slab above weak layers. There have been reports of a poor bond to underlying sun crust layers on south slopes and surface hoar crystals on north slopes, especially north and south of Nelson in the Selkirk Range.
At this point we are uncertain about how long this problem will take to heal and suggest a more conservative approach to terrain to handle this uncertainty.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 18th, 2022 4:00PM
