Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Regions
Kootenay Boundary.
Avalanche danger is increasing with the added load of new storm snow. The cooling trend with this storm is expected to bring enough snow to below treeline elevations to produce avalanches.
Confidence
Poor - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
Overnight and Sunday: Moderate to locally heavy precipitation overnight as the arctic front collides with Pacific moisture. Expect strong westerly winds ahead of the arctic air, and moderate northerly winds after the passage of the cold front.Monday: Precipitation should end during the day. Expect clearing skies and cold valley temperatures.Tuesday: Clear and cold with moderate Northeast winds.
Avalanche Summary
We have received no new reports of avalanche activity, but observations have been limited. Avalanche activity is expected to increase throughout the weekend with forecast snow and wind. If you have been out in the mountains and observed recent avalanche activity, please report it to [email protected]
Snowpack Summary
Snow depth is typically 80-110cm at treeline with 60 to 70cm of well settled snow sitting on the October crust located just above the ground. Little is known about the bond to this crust; however, limited reports suggest that it is currently well bonded. The snow surface on sun exposed alpine slopes, and all slopes below treeline, has been subject to daily melt-freeze cycles. Large surface hoar has also formed on all aspects. Although it has been melting on south aspects during the day, it has likely been regrowing overnight. If you are traveling in the mountains, now is a good time to make note of these surface conditions which may become persistent weak layers once buried by a sufficiently cohesive slab.
Problems
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.
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.