Although the frequency of natural avalanches has gone down recently, the possibility of triggering a large, destructive avalanche is still very real. See the
Forecasters Blog for more insight into this tricky situation.
Summary
Confidence
Fair - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
The ridge of high pressure continues to dominate the forecast. Dry cold arctic air has moved into the region and will remain for the next few days, then towards the end of the weekend, we will see a return to more seasonable temperatures and precipitation.For a more in-depth look at upcoming weather conditions, check out the:
WEATHER OUTLOOK Friday night: Clear with a few clouds, freezing level at valley bottom, no precipitation in the forecast, ridge top winds from the north to 20 Km/h. Alpine temperature inversion.Saturday: Sunny, freezing level at valley bottom, ridge top winds from the north around 15 Km/h.Sunday: Sunny, with a few clouds, freezing level at valley bottom, ridge top winds light to 15 Km/h from the SE.Monday: Cloudy with isolated flurries, 5 to 10cm of precipitation, freezing level at valley bottom, light ridge top winds.
Avalanche Summary
Natural avalanches are still occurring in the forecast area. We've also had reports of cornice failures that triggered avalanches.Conditions are ideal for rider triggering right now. We have received numerous reports of skier triggered avalanches, many of which have released quite deep in the snowpack. Several were remotely triggered from a considerable distance and produced large avalanches.
Snowpack Summary
The storm slab about 1.5 metres thick overlies a persistent weak layer, (surface hoar/facet/crust combo) that was formed during the preceding month of cold dry weather. The storm slab appears to be gaining strength with settlement and warm temperatures but the persistent weak layer beneath it remains widespread at all elevations and aspects. Although this weak layer is not as reactive as it has been, it's still a very real concern. Surface hoar and near surface facetting is occurring on protected/shaded aspects. solar aspects are moist to quite high elevations during the day, with sun crusts forming at night.Large settlements and whumpfs are still being reported indicating the ability of this weak layer to fail and propagate over large distances. Touchy conditions will remain in place for the near future. With the winds changing to north east, wind slab development at tree line may change to south east slopes.In many wind loaded areas, a slab of up to 1.5m thick overlies the persistent weak layer creating ideal conditions for very large avalanches. Weak basal facets exist in some areas, but triggering has now become unlikely.
bcorrigan,
Avalanche Canada
