Avalanche Forecast
Issued: Dec 1st, 2017 8:00AM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
andrew jones,
Parks Canada
Pockets of wind slab are the primary concern for human triggering today. Take the time to dig down and test the November 26th crust before committing to larger slopes.
Summary
Weather Forecast
A frontal system moves in this afternoon bringing 6cm of accumulation today and 8cm overnight. Winds will be moderate from the SW and freezing levels will hover around 1100m. A ridge of high pressure is expected to build on Sunday, deflecting moisture to the north and leaving Rogers Pass with mainly dry conditions for the rest of the week.
Snowpack Summary
The November 26th crust layer is easily identified down 65cm. It separates the moist and warm lower snowpack from the cold and dry upper snowpack. Stability tests from yesterday show that new snow is bonding well to the crust at tree line. The recent storm snow is variable at higher elevations and may include reactive pockets of wind slab.
Avalanche Summary
Five size 2 natural avalanches were observed in the highway corridor from very steep, wind-loaded start zones on the north face of Mt Macdonald. Steep, wind loaded features are the number one avalanche concern heading into today.
Confidence
Forecast snowfall amounts are uncertain
Problems
Wind Slabs
Successive waves of precipitation have arrived with strong southerly winds in the alpine. The storm snow seems to be bonding well to an existing crust (Nov. 26), but pockets of wind slab remain a concern. Human triggering of wind slabs is possible.
Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Dig down to find and test weak layers before committing to a line.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Dec 2nd, 2017 8:00AM
