Regions
Banff Yoho Kootenay.
Natural activity has slowed down, but human triggering remains likely. Give the snowpack some time to heal. SH
Weather Forecast
West winds will be light gusting strong on Thursday with no snow expected. Alpine temperatures will stay below freezing throughout the day. There should be a fair amount of sun throughout the forecast region.
Snowpack Summary
85-100cm of storm snow has fallen in the Sunshine, Kootenay and Yoho areas, with 40-60cm around Lake Louise and Bow Summit since Mar 2nd. This storm snow has overloaded the Feb 10th layer of facets, surface hoar and sun crust, and in thinner snowpack areas, the deeper basal facet layer, causing large, destructive avalanches with wide propagations.
Avalanche Summary
Some solar activity up to size 2 in the Mount Field area today. We have seen a large natural avalanche cycle up to size 3.5 over the past week, with wide propagations on many different aspects and elevations. Also, skier triggered avalanches including remote triggered slides to size 3 have been occurring frequently in the past few days.
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.
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.