The hazard is starting to increase with warmer temps, more wind and more snow. Pull back into more conservative terrain as things change.
Ski conditions are good, but the reactivity of the persistent weak layer is highly variable. If this layer is triggered, it can produce a large avalanche.
30-50 cm of recent snow, increasing SW winds, and warming temperatures are forming wind slabs in alpine and exposed treeline locations. Winds are forecast to increase to high on Monday which will increase the likelihood of this problem.
A layer of facets and/or surface hoar is down 40-100 cm. Reactivity is highly variable across the region, producing variable results in pit tests. Dig down to check whether the layer exists, and ease into the bigger terrain. If this layer is triggered, it will be large.
A couple of skier-triggered avalanches up to size 2.5 occurred on Saturday and Sunday. One was a small wind slab on Bow Peak, and the larger one appeared to fail on a persistent layer down 50-60 cm on Mt Bourgeau.
Several other natural avalanches up to size 3 in the past 48 hrs, were observed during a flight on Sunday, failing as wind slabs or persistent slabs.
New wind slabs are forming at treeline and above with moderate to strong SW winds. 20-50 cm of snow over the March 8 rain crust, which extends up to 1900 m on all aspects, with buried sun crusts at higher elevations. The Jan 24 persistent layer is down 40-110 cm, and is primarily surface hoar at treeline and below in Kootenay and Yoho, and facets at all elevation bands in other areas. Below this, the snowpack is well settled with no significant weaknesses.
Monday: 2-10 cm of snow with the most near the divide. Winds are increasing to strong out of the SW with freezing levels rising to 2200 m Monday night. Snow picks up in the evening.
Tuesday-Thursday: The forecast for the middle of the week is for strong winds, 20-50+ cm of snow, and freezing levels up to 2500 m. Stay tuned...
