Avalanche Forecast
Issued: Nov 27th, 2011 9:00AM
The alpine rating is Wind Slabs, 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 trailing cold front should have moved through the Interior ranges by late Sunday. On Monday a weak ridge of high pressure should bring drier conditions, maybe even some sunshine. It would be nice to get out and see what the last storm brought to the mountains. The weak ridge looks like it will be over-run on Tuesday by a Pacific disturbance that should bring light to moderate precipitation and light northwest winds to all of the interior ranges. Unsettled conditions are forecast to continue on Wednesday, ending sometime Wednesday night or Thursday morning.
Avalanche Summary
Explosive control in the Dogtooth resulted in smaller more stubborn releases to ground up to size 1.5 in the alpine on a north aspect. I suspect that there has been a natural cycle on Sunday when the freezing level was at 1800 metres and the southwest winds were howling.
Snowpack Summary
There is a lot of variation in the snowpack in this region. There is more snow in the Dogtooth area near Golden than there is further south near Invermere and Kimberley. There is probably quite a bit of snow to the west, in areas like the Bugaboos and Jumbo. We don't have any information yet from operators in the west of this region. In the early season we get most of our information from the Dogtooth. We know that there is a weak facetted layer at the ground that has been failing in the last week and resulting in very large avalanches. There has been 60-80 cms recently with strong winds and high freezing levels, creating a cohesive slab above the weak basal layer. In the higher alpine terrain there may be a rain crust from October. The storm and wind-slab instabilities should settle and bond over the next day or two. Any deeper weak layers may continue to be a problem. The danger ratings are steering towards moderate to reflect the storm layers improving. If we see evidence of very large naturals when it clears on Monday, we may change our course!
Problems
Wind Slabs
Aspects: North, North East, East.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Storm Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Nov 28th, 2011 8:00AM