A warm storm may bring 10-15cm on Thursday. Local amounts may be more. Danger ratings will be directly linked to the amount of new snow and wind transport.
Weather Forecast
A warm weak storm Thursday may bring 10-15cm of snow and moderate wind gales. Supposed to be most intense by noon Thursday with 1700m freezing level. The accompanying snow transport may be enough to overload some slopes but the the overall intensity, amounts, and timing is uncertain. We have been disappointed before.
Snowpack Summary
Only 5-10cm of snow arrived Tuesday night thus little change; however, this will continue to be transported onto weak sandwiched wind slab layers in the lee aspects. The main concern remains the top 25cms of the snowpack. Some wind slabs may be reactive on a already weaken, faceted snowpack at exposed tree line, alpine, and crossloaded features.
Avalanche Summary
West of Jasper on Sunday a skier triggered a soft slab. Two skiers were on a crossloaded slope. One escaped to the side but the second was caught and slid for 70m. He was buried shallow and self excavated. Average crown depth 75cms. Wednesday's helicopter flight around Columbia Icefields only observed a few size 1-1.5 NE Alpine-TL.
Confidence
Timing, track, or intensity of incoming weather system is uncertain on Thursday
Problems
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 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.