Regions
Banff Yoho Kootenay.
We expect an avalanche cycle over Thursday & Friday. Stay clear of steep gullied terrain where loose snow avalanches are likely.AVALANCHE CONTROL FOR MT. BOURGEAU, SUNSHINE ROAD ON THURSDAY - PLEASE NO RECREATIONAL ACTIVITIES IN THIS AREA
Weather Forecast
10-15cm of snow can be expected between now & the end of Friday on top of the 25 we have so far. The wind is will pick up on Thursday midday (Moderate West), peaking overnight, and moderate - strong through Friday. Temperatures will also rise with freezing levels climbing to 1800 m. We expect a small avalanche cycle with these inputs.
Snowpack Summary
With the forecast for moderate to strong West wind, the 15-25cm of recent storm snow will continue to build windslabs in the alpine & treeline. The overall snowpack has become weaker from the facetting process but is still supportive. In some areas the upper snowpack is comprised entirely of facets with no cohesion.
Avalanche Summary
Over the past week, several skier triggered and natural loose snow avalanches to size 2 have been reported in steep terrain gaining mass as they travel and running far. On Tuesday, forecasters were able to ski cut a size 1.5 windslab that entrained facets and ran for 700m near the Simpson slide paths in Kootenay NP.
Problems
Loose Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.
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.