Avalanche Forecast
Issued: Nov 23rd, 2012 8:38AM
The alpine rating is Storm Slabs and Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Poor - Due to limited field observations
Weather Forecast
The storm that arrived overnight Thursday moved out of the region Friday. Incoming air is looking cooler and drier. Precipitation: no significant snow or rain forecast through Monday. Wind: light SE Saturday veering to light NW Sunday and backing to the West on Monday. Temperature:Â cooling with below freezing temperatures at all elevations overnight and around 800m or 900 m during the day. Alpine temperatures around -5 to -10C. You're likely to see at least some sun this weekend, more likely on Sunday.
Avalanche Summary
In the limited reports we have, Friday's storm snow is quite reactive with natural avalanches to size 1.5 reported near treeline in the Whistler area. I suspect the arrival of forecast cooler temperatures will end natural activity; however, I suspect human triggering may still be worth thinking about at higher elevations. Explosive testing in the Whistler area only released few and small avalanches on the the early Nov. crust.
Snowpack Summary
The total snowpack depth at treeline is around a metre. Alpine areas are deeper but more variable with fat drifts and boney rocks. Most slopes below treeline are still below threshold depths for avalanches. Weaknesses likely exist within the recent storm snow, but should heal quickly. The main snowpack feature worth noting is a rain crust buried in early November and now down around 80cm at treeline as as deep as 1.5m in alpine areas. A weak layer of facets on top of and within this crust is worth remaining suspicious about (sudden collapse fracture character with propagation potential with snowprofile/snowpack tests; however, explosive testing near Whistler didn't generate many results). Widespread whumpfing and cracking on this layer has also been reported from the Whistler area. Because this weakness is so close to the ground in most areas, associated avalanche activity will likely be limited to slopes with smooth ground cover (e.g. scree slopes, rock slabs, summer firn, glaciers, etc.). For more information check out the telemarktips.com forum , the Mountain Conditions Report, and Wayne Flann's Avalanche Blog.
Problems
Storm Slabs
Aspects: North, North East, East, South East, South.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Nov 24th, 2012 2:00PM