South Columbia

Warming and sunshine will drive avalanche danger this week. Plan to start your day early and to avoid large sun-drenched slopes during the heat of the day.

On Saturday there was a report of a natural cornice fall that triggered a size 3 persistent slab on a steep, rocky, north-facing slope. There was also some minor loose wet sluffing to size 1.5 on steep sun-exposed slopes in the afternoon. On Friday, just outside the northern extent of the region, there was a report of a very large (size 4) persistent slab on a large south-facing slope that was triggered by new snow loading. This avalanche likely failed on the late February interface.

High

MONDAY: Cloudy with a chance of flurries and sunny breaks in the afternoon. The freezing level climbs to 1600-1800 m and winds are moderate from the N-NE. TUESDAY: Mainly sunny. The freezing level is around 2000 m and winds remain light to moderate from the N-NE. WEDNESDAY: Mainly sunny. The freezing level spikes to 2300-2600 m and winds are light from the NE.

Light new snow covers a variety of old surfaces including crusts on solar aspects, moist snow up to treeline, and dry snow or fresh wind slabs in the alpine on shaded aspects. Approximately 40-50 cm of settled storm snow sits on a melt-freeze crust buried on Mar. 22. The late February persistent weak layer is an aspect dependant mix of surface hoar, facets and/or a thick crust down around 60-110 cm below the snow surface. Commercial operators continue to see hard sudden planar results in snowpack tests, which suggests that wide fracture propagations are possible. Cornices continue to be described as large and fragile. Expect loose wet avalanches and natural cornice falls during periods of strong solar radiation and/or daytime warming.