Avalanche Forecast
Issued: Nov 29th, 2016 3:49PM
The alpine rating is Storm Slabs and Cornices.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Moderate - Forecast snowfall amounts are uncertain on Wednesday
Weather Forecast
Snow developing overnight with moderate southwest winds and freezing levels around 1000 metres. Expect 5-10 cm by Wednesday morning and another 5-10 cm during the day. Light westerly winds and a few cm of snow or flurries on Thursday. The next major storm is forecast on Friday, expect strong southwest winds and 20-35 cm of snow above 1500 metres.
Avalanche Summary
Some reports from Monday of skier controlled soft slab avalanches up to size 1.5 where the surface snow has slabbed up above a less dense (one finger over fist) layer of recent storm snow. However, explosives control on Sunday produced several soft storm slab avalanches on a variety of aspects and elevations. Most of the activity was in the size 1 range, although a few results to a size 2 were also noted. A few size 2 cornice collapses were also triggered with explosives in alpine terrain. Looking forward, relatively calm weather should allow for strengthening and settlement in the snowpack, and avalanche activity should taper-off. I'd still remain cautious of human-triggered storm slabs, especially in steeper, high elevation terrain.
Snowpack Summary
Snow depths increased rapidly last week bringing treeline snow depths to about 200 cm. Much of this recent storm snow has settled and gained significant strength. That said, the last burst of wind and snow on Saturday and Sunday created reactive soft storm slabs which appeared to be especially touchy in higher, wind-exposed terrain. Stormy weather also encouraged significant cornice growth, and new cornices are reported to be unseasonably large and fragile. Over a metre below the surface you'll find the thick mid-November crust. The reports we've received suggest a reasonable bond at this interface; however, I'd remain suspicious of this layer until the snowpack adjusts to the weight of all of the new snow. This may take a few more days. Below the crust, the snowpack is strong and well-settled.
Problems
Storm Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Cornices
Aspects: North, North East, East, South East.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Nov 30th, 2016 2:00PM