North Columbia

Convective flurries and moderate southwesterly winds may create small wind slabs in lee features below ridgetops.

Moderate - Forecast snowfall amounts are uncertain

TUESDAY: Cloudy with flurries, 3-5 mm rain/snow. Moderate southwesterly ridgetop winds. Freezing level around 2000m.WEDNESDAY: Mostly cloudy. Light to moderate southwesterly ridgetop winds. Freezing level around 2000m.THURSDAY: Mix of sun and cloud. Light southeasterly ridgetop winds. Freezing level around 2100m.NOTE: The convective flurries which are common during this time of year can result in widely varying snowfall amounts throughout a region. These spring squalls routinely drop 20+ cm of snow in one valley while the adjacent drainage remains dry. For this reason, the distribution of avalanche problems associated with new snow, such as wind slabs, can vary greatly within a region.

Two size 2.5 slab avalanches were reported in this region on Sunday. One was triggered by a falling cornice and the other by a small loose wet avalanche. Falling cornices triggering large avalanches is currently our primary concern.

Triggering large avalanches on facets near the bottom of the snowpack is currently our primary concern. On high north facing terrain, which is currently where the best skiing can be found, the problem is the possibility that if a large cornice falls on a steep slope, it will trigger this layer. On solar aspects, the problem is small loose wet or wind slab avalanches stepping down to this layer or skier triggering the layer by hitting a shallow spot in a large, steep, and rocky alpine face. Additionally, convective flurries and moderate southwest winds may form fresh wind slabs on lee features at Treeline and above on Tuesday. Fresh snow combined with warm temperatures will increase the likelihood of small loose wet avalanches on all aspects at Treeline and below.