South Coast

Fair - Timing, track, or intensity of incoming weather system is uncertain

The next Pacific frontal system will cross the South Coast regions today with strong winds and moderate to heavy precipitation. Generally unsettled conditions are expected for Wednesday and Thursday with light intermittent snowfall and sunny breaks.Tuesday night: Freezing level drops to around 200m. Snowfall amount 10-20cm, m, ridge top winds gusting to70km/h  from the SW.Wednesday:  Freezing level around 500m. Intermittent snowfall with 5 to 10cm accumulation, ridge top winds 30-50km/h from the W.Thursday: Freezing level around 700m.  Another wave of moisture through the south of the forecast area, with 15 to 20cm, ridge top winds 30-50km/h from the west.Friday: Freezing levels around 300m.  No precipitation in the forecast, winds light at ridge top from the south.

On Saturday skiers in the Coquihalla area triggered a size 2 slab avalanche on a steep slope in open trees, below treeline. One partial burial occurred, sustaining some injury. One natural cornice release triggered a size 2.5 slab avalanche on the slope below and explosives control produced numerous 2.5-3.5 avalanches. Nothing was reported from the region on Sunday but this may be due to a lack of observers. It is expected with the large amount of new snow over Sunday night that natural storm slab avalanches likely occurred on Monday.

In the last week, the Northern parts of the region have received over 1m of new snowfall and the Southern areas have seen over 1.5m. This snow has settled into storm slabs which are typically 50-70cm thick in the north and 80-120cm in the south. This storm slab overlies a variety of old surfaces consisting of facets, surface hoar, a scoured crust, wind press, or any combination of these. Particularly of concern is the combination of buried facets on a crust being unusually reactive at treeline and below treeline elevations. Whumpfing and widespread avalanche activity further indicate a poor bond between the new snow and these old surfaces.Strong to extreme winds are shifting the new snow into deeper, reactive wind slabs in leeward terrain.The mid and lower snowpack are generally strong and well-settled. Although basal facets and depth hoar are likely to exist in the north of the region.