Avalanche Forecast
Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Little Yoho, Sunshine, West Side 93N.
Lots of uncertainy about how much snow will fall with this storm, but with strong winds and new snow the avalanche hazard will rise on Wednesday.
If snowfall amounts are higher than forecast the danger may increase to HIGH in some areas. Monitor snowfall amounts closely and choose more conservative terrain if needed.
Confidence
Moderate
Avalanche Summary
We expect an increase in avalanche activity on Wednesday with new snow and strong west winds.
On Sunday, we received two separate reports (Report 1/Report 2) of large, human-triggered avalanches in the Highway 93N backcountry. Both avalanches involved a stiffer slab failing on the deep persistent facets/depth hoar on N/NE aspects. Recent natural avalanche activity on this layer has been minimal, but it remains active and continues to be the primary avalanche concern.
Snowpack Summary
Increasing west winds and new snow will create wind slabs in lee areas at treeline and in the alpine. This new snow will sit over a weak faceted midpack, with very weak basal facets/crusts near the ground. Western areas of the forecast region have similar layers but a slightly deeper, denser snowpack with fewer facets. Snowpack depths at tree-line are 40-60 cm in eastern areas and 100 cm west of the divide.
Weather Summary
Tuesday night: Snow begining in the evening with 5 cm expected overnight accompanied by strong west winds.
Wednesday: Snow continuing with an additional 5-10 cm expected throughout the day. Strong west winds continue through the day. Treeline temperatures remain steady near -7°C.
Note: Local snowfall amounts may be higher than expected with this storm.