Regions
Banff Yoho Kootenay.
The invasion of the Arctic air back over the divide felt like a Lion today,,, or was it a Groundhog? It would seem the February cold snap is not finished with us yet.
Weather Forecast
Arctic air pushed back through from the prairies Friday with cold heavy air flowing up the main valleys squeezing small amounts of snow out of the retreating Pacific air. This Arctic air will dominate through the weekend before it begins to retreat. Light winds and sunny skies should make this tolerable if you can endure the cold start.
Snowpack Summary
Cold temperatures continue to weaken the surface snow. Wind effect is common in the alpine and several recent crusts can be found on steep solar slopes. Despite the weakening slab above it, Jan 17 surface hoar lingers down 40-60 cm in isolated locations and produces hard, resistent shears. A weak basal snowpack exists in thin snowpack areas.
Avalanche Summary
No reports of slab avalanches have come in today however loose snow avalanches or 'point release sluffs' have become common in steep terrain. Given the right terrain these sluffs can amount to significant avalanches: they start slow but gain mass quickly and would be very 'real' for those caught in a terrain trap such as above a cliff or in a gully
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.