Regions
Banff Yoho Kootenay.
Natural avalanches are likely. We are in a natural avalanche cycle, and will be for the next 24 hours.
Weather Forecast
A second pulse from the pineapple express will hit the Rockies tonight and tomorrow, bringing up to 30cm of snow at higher elevations and rain below 1900m. Winds will be moderate to strong from the west. Temperatures will continue to be mild for this time of year (freezing level rising to 1900m), with no cooling overnight.
Snowpack Summary
A warm, windy night brought 15-20cm of dense snow. This has created very touchy storm slabs in the alpine and at tree-line. Below tree-line, there was rain to 1900m, creating unstable surface conditions.
Avalanche Summary
We are currently in a natural avalanche cycle, and will be for the next 24 hours at least. A field team in Yoho remotely triggered a size 2 slab avalanche while moving through moraines above Takakkaw Falls. They noted that conditions were very touchy and retreated. Below tree-line, numerous loose slides to size 1.5 were observed in Yoho.
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.
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.