Avalanche Forecast
Issued: Dec 30th, 2011 9:54AM
The alpine rating is Storm Slabs, Wind Slabs and Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Good - -1
Weather Forecast
One last pulse out of the recent active weather system will affect the region Friday evening before a strong ridge of high pressure anchors itself over Eastern BC for the weekend. Skies clear and cooler temperatures pervade under the ridge which will bring freezing levels down to valley bottom. On Saturday you can expect moderate winds out of the W and a daytime high of -9 with overnight lows dropping slightly to -12. A weakening system slides into the region Monday bringing light precipitation and cloudy skies.
Avalanche Summary
Reports of natural large avalanches up to size 3 have occurred throughout the South Columbias. Continued reports of rider triggered avalanches up to size 1.5, and natural cornice failures triggering slopes below up to size 2.5. The focus is on elevations between 1300-2100m, and mainly on North-South aspects. This avalanche cycle indicates that the December 24th surface hoar and the mid-December surface hoar layers have reached the tipping point and are producing large slab avalanches. Check out the Forecasters Blog to see an updated avi picture. It clearly indicates how touchy the surface hoar layer is on convexities and low angle terrain.
Snowpack Summary
Up to 100 cm have fallen across the region since Boxing Day. This meter of snow sits on top of a weak layer that is widespread across the region; the mid December surface hoar/facet/crust combination. In tests this layer fails with sudden planer characteristics meaning that the failure has a lot of energy in it. This layer can be found at all three elevation bands and is still quite active. This layer will continue to be reactive to increased load in form of snow, rain, wind or a recreating human. Below the mid December weak layer lies a well consolidated & strong mid pack.
Problems
Storm Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
Aspects: North, North East, East, South East, South.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 31st, 2011 8:00AM