South Columbia

New snow and southerly winds will be driving avalanche danger on Tuesday into Wednesday. Avoid exposure to avalanche terrain during periods of rapid loading by rain, snow, or wind.

Low - Intensity of incoming weather systems is uncertain

We're looking at a brief lull in the active weather pattern on Wednesday, before the next system arrives on Thursday with modest amounts of snow.WEDNESDAY: Clearing throughout the day. Moderate westerly ridgetop winds. Freezing level around 1200 m.THURSDAY: Snow (10-15 cm). Moderate southwesterly ridgetop winds. Freezing level around 1000 m. FRIDAY: Cloudy with sunny breaks during the day and isolated flurries. Moderate south west ridgetop winds. Freezing level around 1000 m.

On Monday, several storm slabs to Size 2.5 were reported near Rogers Pass, on northerly aspects between 2000 - 2700m. On Saturday we received reports of a skier-triggered Size 1 storm slab on a NW aspect at 2150m elevation in Rogers Pass. See here for the MIN report. A natural avalanche cycle is expected on Tuesday with the incoming snowfall. We currently have very limited observations in this region. Please submit your observations to the Mountain Information Network (MIN).

The warm temperatures and rain on Sunday resulted in a crust (November 27th crust) up to approximately 1900m (higher in the Monashees), which was covered by 5 - 20 cm of snow at higher elevations as temperatures cooled significantly. This November 27th crust could prove to be an excellent sliding layer when additional snow falls on Tuesday into Wednesday. Lower down in the snowpack, 15 to 30 cm of snow sits on a 2-4cm thick crust formed on November 23rd. The heavy rain last week rapidly shrunk the snowpack and transitioned much of the snowpack from dry to moist snow. The depth of the snowpack varies greatly with elevation. Recent reports suggest the average depth is 200+cm in the alpine, 100-150cm at treeline, and decreasing rapidly below treeline where the primary hazards are rocks, stumps, and open creeks. A major feature in the snowpack is a 3-5 cm thick crust which was formed around Halloween and can be found approximately 70-100cm down at treeline elevations. We currently have very limited snowpack observations within this region and it is critical to supplement this information with your own observations.