South Columbia

A Special Public Avalanche Warning (SPAW) is in effect for this region. Warming temperatures and strong winds are expected to give way to a natural avalanche cycle. Seek out low angle terrain free of overhead hazard.

THURSDAY NIGHT - Cloudy with flurries, 5-10 cm / south to southwest winds , 25-65 km/h / freezing level 1100m / alpine low temperature near -5FRIDAY - Mainly cloudy with flurries, up to 10 cm / south to southwest winds, 40-80 km/h / freezing level 1500m / alpine high temperature near -1SATURDAY - A mix of sun and cloud with isolated flurries / south to southwest winds, 20-40 km/h / freezing level 1000m / alpine high temperature near -7, low temperature near -12SUNDAY - Cloudy with sunny periods and isolated flurries / southerly winds, 20-45 km/h / freezing level 1500m / alpine high temperature near -2, low temperature near -9

Moderate - Freezing levels are uncertain

Numerous natural and human triggered avalanches up to size 2.5 were reported in the South Columbia region on Wednesday. Several of these avalanches were triggered from a distance (remote triggered).

60-95 cm of recent storm snow sits on a weak layer that consists of facets (sugary snow), surface hoar (feathery crystals) and a sun crust on south aspects. The storm came in with moderate to strong winds that continue to persist throughout the region, creating widespread slab formation.Another weak layer of surface hoar and sun crust that formed in mid-November is up to 120 cm below the surface. This layer is most likely to be a problem in areas where the surface hoar sits on the sun crust. This combination is most likely found on steep, south facing slopes at treeline. The potential may exist for storm slab avalanches to step down and trigger this deeper layer, resulting in large avalanches.At the base of the snowpack is a crust that formed near the end of October. Concern for this layer is dwindling but it may still be worth considering in places such as steep, rocky, alpine terrain, especially where the snowpack is shallow. It would likely take a large trigger such as a cornice fall to produce an avalanche on this layer.