New wind slab formation is expected on Thursday as the wind shifts to a northwest direction. Given the recent shifting wind directions, reactive slabs should be expected on all aspects in exposed terrain.
New wind slab formation is expected on Thursday resulting from forecast strong NW winds. Any areas which had outflow winds on Monday and Tuesday may have reactive wind slabs and stubborn older wind slabs from the weekend may still be lingering. Given the shifting nature of the recent winds, wind slabs should be expected on all aspects in exposed terrain.
Arctic high pressure remains for Thursday but the wind is expected to shift to a NW direction. Unsettled conditions are expected for Friday in advance of a weak Pacific storm system which is currently forecast to push inland on Friday night or early Saturday.
Wednesday Overnight: Mainly clear, moderate to strong NW winds, treeline temperature around -20 °C.
Thursday: Mostly sunny, moderate to strong NW winds, treeline high around -20 °C.
Friday: Increasing cloud cover, light to moderate SW winds, treeline high around -20 °C.
Friday Night and Saturday: Light snowfall, moderate to strong SW winds, treeline high around -16 °C.
No new avalanches were reported on Tuesday. On Monday, the Avalanche Canada field team reported a few size 1 loose dry avalanches on steep alpine slopes. On Sunday, explosives were triggering wind slabs up to size 1.5 in the far south of the region and on Saturday, several natural wind slab avalanches had been reported.
On Thursday, new wind slabs are expected to develop in response to the forecast strong NW winds. Stubborn old wind slabs from the weekend may also still be reactive in isolated terrain such as steep, unsupported terrain features. Given the shifting wind directions, wind slabs should be expected on all aspects in exposed terrain.
Over the weekend, the region typically saw 10-20 cm of new snow. This new snow was accompanied by strong SW winds which formed reactive wind slabs in exposed terrain. On Monday, some areas of the region may have had outflow (NE-E) winds which may have formed new wind slabs on south and west aspects. Strong NW wind on Thursday is expected to form new wind slabs on south and east aspects. Given the variable nature of the recent wind, slabs should be expected on all aspects in exposed terrain.
An early season crust and facets can be found near the base of the snowpack. This layer now appears to have gone dormant through most of the region but could still be reactive in some shallow snowpack areas.
Snowpack depth at treeline typically ranges from 100-200 cm, with higher values in the western part of the region and tapering to the east. In the far southwest of the region, the height of snow is closer to 300 cm.
