Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches possible, human triggered probable.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches possible, human triggered probable.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches possible, human triggered probable.
Regions
Banff Yoho Kootenay.
Avalanche control on highway 93N Sunday, avoid travel on Hector, Andromache, Dolomite, Helen Lake trail, Observation, Silverhorn, Noyes and Waterfowl Lake Gullies. Dangerous avalanche conditions persist in the forecast region.
Weather Forecast
Valley bottom temperatures will drop Saturday night with a slight inversion forecast for Sunday, alpine temps expected around -12 to -17. A brief break in precipitation Sunday will bring clears skies before another small system moves in Monday. Winds are expected to remain in the light to moderate range through Sunday.
Snowpack Summary
15-25cm of new snow and moderate winds have developed new storm slabs in the upper snowpack. The main concern in the snowpack continues to be the three persistent weak layers of surface hoar and/or facets that are found between 50 and 100cm down. We continue to observe sudden test results, whumphing and large propagations on these layers.
Avalanche Summary
Natural activity reported Saturday on Bourgeau Left, limited observations due to visibility but the powder cloud reached the Sunshine parking lot (suspect a size 3). Big avalanches with explosives over the last few days show that snowpack remains prime for triggering. Some avalanches ran full path and put dust or debris on roads.
Confidence
Problems
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.