Avalanche Forecast
Issued: Jan 7th, 2012 9:40AM
The alpine rating is Wind Slabs, Persistent Slabs and Cornices.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Fair - Forecast snowfall amounts are uncertain on Sunday
Weather Forecast
The Pacific system that hit the north coast today is moving inland this evening. Very strong winds on the coast are expected to diminish to about 70 km/hr from the southwest by the time they reach the Cariboos and the Monashees. I expect that there will be about 15-20 cm of new snow by Sunday morning. The freezing level is forecast to rise to about 1500 metres on Sunday morning, and then lower back to 1000 metres by Sunday evening. Another pulse of snow is forecast for Sunday evening that looks like it will bring another 10-15 cm combined with moderate southwest winds. The snow should end during the day on Monday after leaving about 5cm. Cooler clear weather is expected Monday night and should continue for Tuesday.
Avalanche Summary
A natural cornice failure from Friday on an east aspect at 2600 metres caused an avalanche size 2.5
Snowpack Summary
Strong southwest winds and moderate to heavy precipitation has begun to build new windslabs in the alpine and at treeline. The recent snowfalls add up to about 60-80 cm of "storm" snow that has been available for wind transport. The warm temperatures and high freezing levels caused the wind transported snow to become a well consolidated slab. There are two rain crusts below 1550 metres. The rain crusts are variable, but they are giving planar results in tests. At treeline the storm snow is reported to be giving sudden planar results down 40 cm, and the surface hoar/crust layer that is down 80cm is also giving sudden planar results. This tells me that the new load of snow that we are expecting may activate these weak layers. The mid-pack is reported to be strong, and I have not heard anyone talk about early season layers deep in the snowpack.
Problems
Wind Slabs
Aspects: North, North East, East.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Cornices
Aspects: North, North East, East.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Jan 8th, 2012 8:00AM