Summary
Confidence
Fair - Forecast snowfall amounts are uncertain on Thursday
Weather Forecast
Wednesday night: Approximately 10 cm new snow. Extreme wind speeds, gusting to 90km/h from the SW. Freezing level rising to around 1000 m.Thursday: continued snowfall, with up to 10cm expected. Winds gusting to 60 km/h, initially SW'ly then becoming SE'ly. Freezing level around 500 m. Friday: Mostly dry, with partial clearing. Winds easing to light or moderate from the SW. Freezing level dropping to sea level.Saturday: Moderate snowfall, moderate SE'ly winds, freezing level around 100 m.
Avalanche Summary
A size 1 avalanche was triggered by a skier on 29th Dec in a pocket of wind slab. I suspect similar events are possible with the current conditions, although there have been no further reports since this event. A natural size 2 slab avalanche was observed in the Hankin area that would have happened around December 28th. Most likely triggered by a cornice fall on a North facing slope, it stepped down deeper in the snowpack, suspecting the November 6th crust. For more information check out the report
here.
Snowpack Summary
The snowpack is generally shallow (about 1m deep) and strong winds have scoured some alpine slopes to ground. Wind slabs exist in many wind-exposed areas. Their distribution is quite variable and some areas have no wind-effect at all. It is still possible to find cold, low density snow at the surface in wind sheltered areas. Below treeline, very loose cold snow is sluffing easily from steep terrain and early season hazards like exposed stumps and rocks are still present in places. Professionals are still mindful of a facet/crust layer near the base of the snowpack. Although triggering it has become unlikely, it may be possible from a thin-spot trigger point or with a very heavy load (e.g. cornice fall). A size 2 natural slab avalanche triggered by a cornice fall that occurred on December 28th in the Hankin area illustrates that caution is still warranted for this layer.
jfloyer,
Avalanche Canada
