South Columbia

This forecast is based on very few field observations and a high level of uncertainty exists. A conservative approach to terrain selection is critical until more snowpack data becomes available.

Moderate - Due to the number of field observations

Friday: 5-10cm of new snow / Moderate to strong southwest winds / Freezing level at 900mSaturday: Light flurries / Light and variable winds / Freezing level at 400mSunday: Mix of sun and cloud / Light and variable winds / Freezing level at valley bottom with alpine temperatures dropping to about -11

On Wednesday, explosives control triggered numerous storm slab avalanches up to size 2 in west to northeast facing alpine terrain. Observations were limited at the time of publishing this bulletin; however, a natural storm slab avalanche cycle is expected to have occurred on Thursday in response to recent wind and snowfall. The possibility of human triggering of these storm slabs is expected to continue into the weekend.We currently have very limited observations in this region. Please submit your observations to the Mountain Information Network (MIN).

Between 30 and 45cm of new snow has fallen in the past few days. I'd expect reactive storm slabs to exist in wind-exposed terrain or in places where the recent storm snow has a weak bond with a series of crusts from late November which lie up to 60cm below the surface.Another feature in the snowpack is a 3-5 cm thick crust which was formed around Halloween and can be found approximately 100cm down at treeline elevations. This layer is generally thought to be stubborn to trigger; however, it may be worth investigating if your travel plans involve large triggers on big, steep, unsupported terrain.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. We currently have very limited snowpack observations within this region and it is critical to supplement this information with your own observations.