Avalanche Forecast
Regions: Bonnington, Grohman, Kootenay Boundary, Kootenay Pass, Moyie, Norns, Rossland, South Okanagan, Ymir.
Lingering wind slabs may remain reactive to human triggers on northerly aspects in the alpine.
Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
Confidence
High
Avalanche Summary
Numerous naturally triggered size 1-1.5 wet loose avalanches were reported on sunny aspects at upper elevations on Sunday.
A large (size 2.5) rider triggered wind slab was reported on a north aspect in the alpine on Friday. The avalanche was triggered from the ridge top and the reported weak layer was surface hoar. See MIN.
Additionally, a snowmobile triggered a large persistent slab avalanche (size 2.5) just north of this region near Haystack mountain (west of Cranbrook). The avalanche occurred in burnt forested terrain on a south aspect at 2200 m. It failed on a 50 to 100 cm deep layer that is suspected to be a sun crust buried in February.
Snowpack Summary
Expect to find a melt-freeze crust on the surface of all aspects at treeline and below and on sunny aspects in the alpine. Solar radiation will break down the crust on sunny slopes throughout the day.
Lingering wind slabs may remain reactive to human triggers on northerly aspects in the alpine.
30-50 cm down there is a sun crust on sunny aspects and surface hoar (3-5 mm) on isolated shady and sheltered slopes.
Another layer of surface hoar or sun crust, aspect dependent, that was formed in mid-February can be found down 80 to 110 cm.
The lower snowpack includes a layer of weak sugary facets near the ground. These facets are slowly gaining strength and no recent avalanches have been reported on this layer. However, we continue to track the layer and watch for any signs of it becoming active.
Weather Summary
Monday Night
Clear skies / 10 km/h north ridgetop wind / Temperature at treeline around -6 C / Freezing level valley bottom
Tuesday
Sunny / 10 km/h north ridgetop wind / Temperature at treeline around -1 C / Freezing level 1900 m
Wednesday
Sunny / 10 km/h southeast ridgetop wind / Temperature at treeline around 1 C / Freezing level 2100 m
Thursday
Mix of sun and cloud / 20 km/h south ridgetop wind / Temperature at treeline around -3 C / Freezing level 1700 m
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet
- Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
- Cornice failure may trigger large avalanches.
Avalanche Problems
Wind Slabs
Lingering wind slabs may remain reactive to human triggers on northerly aspects in the alpine.
Aspects: North, North East, North West.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 1 - 2
Loose Wet
Strong solar radiation will increase the likelihood of wet loose avalanches on sunny aspects in the alpine.
Aspects: South East, South, South West, West.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 1 - 2