North Columbia

Choose conservative terrain in the coming days due to the presence of a persistent slab problem.

Moderate - Due to the number of field observations

FRIDAY: Mix of sun and cloud / wind light north / alpine temperature -14 SATURDAY: Mainly sunny / wind moderate northwest / alpine temperature -15 SUNDAY: Mix of sun and cloud / wind light to moderate north / alpine temperature -11

Reports from the past few days include several natural storm and wind slab 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. These avalanches are failing at the interface between the recent storm snow and the old snow surface. As snow settles and consolidates in the coming days expect to see in human triggered avalanche activity continue even as the stormy period ends.

30-50cm of new snow accumulating over the last week 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 80-110cm 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.