North Columbia

Fresh snow has accumulated at upper elevations along with southwesterly winds. Use caution around ridge crests and lee terrain features, where deposits will be most reactive and may also hide older, recently formed wind slabs.

Moderate - Timing or intensity of solar radiation is uncertain

SUNDAY NIGHT: Cloudy with clear periods / west wind, 10-20 km/h / alpine low -7 C / freezing level 900 mMONDAY: Mix of sun and cloud with isolated flurries, trace accumulation / southwest wind, 10-15 km/h / alpine high -5 C / freezing level 1600 mTUESDAY: Cloudy with sunny breaks and isolated flurries, trace accumulation / south-southwest wind, 15-30 km/h / alpine high -3 C / freezing level 1800 mWEDNESDAY: Cloudy with scattered flurries, up to 5 cm accumulation / west wind, 10-20 gusting to 50 km/h / alpine high 0C / freezing level 2100 m

Late Saturday, storm snow was sluffing in steep terrain with skier traffic and gaining cohesion.On Thursday, a few human triggered loose wet avalanches up to size 1.5 were observed on steep slopes in the afternoon. Evidence of a solar-induced wet slab cycle on west aspect around 2400 m was reported on Friday.On Wednesday the avalanche activity decreased. A few natural and human triggered wind/storm slab avalanches up to size 2 were reported on west and north aspects at treeline and in the alpine.On Tuesday, several natural and human triggered storm/wind slab avalanches 20-40 cm deep and up to size 2.5 were observed on north and east aspects. Two of these were remotely triggered, one by humans and another one by a helicopter. A layer of small surface hoar below the most recent snow may have been the weak layer. Several natural wet slab and loose wet avalanches up to size 2.5 were reported from south and west aspects (see a MIN report from Glacier National Park).

Up to 20 cm snow accumulated above 1600 m Sunday, westerly winds are redistributing fresh snow. On most aspects this covered a melt-freeze crust; on north facing slopes in the alpine, new snow fell over the recent 25-60 cm wind-affected snow and, in isolated locations buried surface hoar. Older wind slabs sitting on surface hoar might still be sensitive to human triggers.Below treeline snow is disappearing rapidly.