Natural avalanche activity has tapered off somewhat, but a few very large natural and human-triggered slides have occurred. Large and destructive avalanches are possible. It is time for conservative terrain choices! Great skiing is found in sheltered areas below treeline.
Multiple vintages of wind slab can be found in the upper 100cm of the snowpack due to persistent wind and snowfall for the past week. Many areas look significantly loaded and primed for human triggering.
Avalanches initiated in the surface wind slab will likely trigger this deeper instability. Large and destructive avalanches are possible. Some recent natural and human-triggered avalanches failed on this layer.
A naturally triggered size 2.5 was observed today in the Hero's Knob area in steep Alpine terrain on an East aspect. The slide looks to be less than 24hrs old and had a fracture line of approximately 150cm deep.
A significant remote triggered large avalanche (reported as size 3.5) occurred Monday in the Black Prince zone. Thanks to those that posted a MIN of this event. This avalanche was very deep and likely ran on the Nov crust layers.
One size 2.5 naturally triggered persistent slab was observed in the Burstall Pass area on Sunday. The avalanche exhibited very wide propagation (250m), but did not run far down slope. The slide was also very deep in some parts of the crown, ranging from 100 to 300cm deep.
Another 2 to 5cm of snow fell in the last 24hrs, bringing the recent storm snow up to as much as 100cm in the past week. Unfortunately the winds have been strong throughout this period. Wind slabs are widespread in the alpine and on lee and cross-loaded features at treeline. These wind slabs are likely to be sensitive to skier traffic. The December 16th crust is down about 75cm, but isn't producing shears. The November crust is now down 100-150cm, and is showing signs of faceting. Any avalanche triggered in the upper snowpack has a strong likelihood to step down to deeper instabilities.
Christmas Eve should bring another cloudy day with light snow. Between 5 and 10cm are possible with moderate SW winds midday increasing to extreme winds (100km/h) by evening. Temperatures will be very mild, with a high of 0 Celsius and freezing levels near 2200m.
More details can be found in the Mountain Weather Forecast.
