North Columbia

Expect the recent storm slab to become more reactive as it continues to settle and consolidate.

Moderate - Forecast snowfall amounts are uncertain on Wednesday

WEDNESDAY: Periods of snow in the southern portion of the region Tuesday into Wednesday, accumulations 5-10cm / wind light to moderate northwest / alpine temperatures -11 THURSDAY: Mainly cloudy with isolated flurries / wind moderate northwest / alpine temperature -9  FRIDAY: Mainly sunny / wind moderate north / alpine temperature -15

Reports from the past 2 days include several explosives controlled and natural storm snow avalanches to size 2.5 in the alpine and tree line. There have also been a few reports of skier accidental and remote (triggered from a distance) avalanches to size 1.5 and 2 at and below tree line. This avalanche activity is failing in the recent storm snow. As snow accumulates and settles in the coming days expect to see in human triggered avalanche activity continue even as the latest forecast storm ends.

30-50cm of new snow accumulating over the past 5 days sits on a wide variety of old surfaces including large surface hoar (weak, feather-like crystals), hard crusts formed by sun or wind, and sugary facets. As the snow load builds and slab properties develop, it will be important to monitor how the new snow is bonding to the old surfaces. Most concerning would be areas that have seen previous surface hoar development, such as sheltered areas at and below tree line and sheltered northerly aspects in the alpine. Additionally, any steep solar aspects where the surface hoar may be sitting on sun crust should be considered areas where this weak layer may be very likely to trigger. A crust which was formed by rain in late November is a major feature in the snowpack and is down approximately 50-80cm at tree line elevations. Snowpack tests suggest the snow above is currently bonding well to it. Snowpack depth decreases rapidly below tree line. Look out for early season hazards such as rocks, stumps, and open creeks.