New snow and strong winds overnight will increase the avalanche danger. New snow may release as loose wet avalanches when temperatures rise during the day.
Summary
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
Moderate snowfall (5-10 cm) overnight with moderate southwest winds and freezing level staying above 1300 metres. Continued light snow on Thursday with moderate to strong westerly winds, freezing levels rising to 1500 metres, and a chance of sunny breaks in the afternoon. Freezing down to valley bottoms on Friday morning with lingering flurries early in the day, becoming mostly sunny with light northwest winds. A mix of sun and cloud on Saturday with westerly winds, there is some uncertainty on the amount of sun at this time.
Avalanche Summary
Some explosives control on cornice on Tuesday resulted in releases up to size 2.5 on northerly aspects. We had a report on Monday of another skier remote triggered avalanche size 2.5 from 200 metres away on a southeast aspect at 2320 metres, believed to have released on the February 27th weak layer. A MIN report from Monday at Gorman lake in the Dogtooth range describes "a lot of cornice failures", as well as "many slides running full path." On Sunday, large cornice releases triggered persistent slabs on slopes below up to size 3.0 in the central part of the region, and a group of skiers remotely triggered a size 2.5 from 6 metres away on a southeast aspect at 2400 metres in the north of the region.
Snowpack Summary
Forecast new snow and wind are expected to develop a new storm slab above a mix of crusts on solar aspects, moist snow up to about 1800 metres, and dry snow or recent wind slabs on shaded high alpine aspects. Cornices continue to be described as large and fragile, and may fail with additional loading from forecast snow, or from high daytime temperatures. Buried persistent weak layers continue to be a concern for remote triggering in isolated areas where crusts are not strong enough to "bridge" the weakness. The late February surface hoar/crust weak layer is down 40-90 cm. This layer is still reactive to human triggers in some places while in other spots it's really tough to trigger, and there's not much of a reliable pattern telling us what exact aspects are most suspect. Deeper weak layers from mid-February and early January are now down 50-90cm and 70-120cm respectively. Triggering an avalanche on either of these layers has become unlikely but still has the potential to produce very large avalanches in isolated locations.
triley,
Avalanche Canada
