South Columbia

Avalanche danger will increase through the day as new snow and wind form touchy storm slabs at upper elevations and rain soaks the snowpack below 1500 m. In the west of the region where less than 25 cm of snow falls, treat avalanche danger as one step lower at all elevations.

Highest snowfall amounts will be in the Selkirks, east of Upper Arrow Lake between Revelstoke and Nakusp.

Saturday night: 5-15 cm new snow. Southwest wind increasing 40-60 km/h. Freezing level 1600 m. Alpine temperature -3.

Sunday: 15-25 cm in the northern Selkirks, 5-10 elsewhere. 40-70 km/h southwest wind. Freezing level 1600 m. Alpine temperature -3.

Monday: Another 5-10 cm of snow by the morning then mostly cloudy during the day. 30 km/h northwest wind. Freezing level 1000 . Alpine temperature -10.

Tuesday: Mix of sun and cloud. 20 km/h northwest wind. Freezing level 1400 m. Alpine high -5.

Avalanche activity over the past few days has primarily been small (size 1-1.5) dry loose avalanches in the top 20 cm and some small cornice failures that did not trigger any slabs. However, each day there have been a few notable slab avalanches. A natural wind slab avalanche size 1.5 was observed on Friday. On Thursday a natural size 3 avalanche was observed on a east aspect at 1800 m in the Valhallas. The crown 100 cm thick, but no other details are known. On Wednesday there was a size 2 skier triggered avalanche on a east facing slope at 2250 m in the southern Selkirks (running on a 30 cm deep crust layer).

With 5-20 cm forecast per 12 hour period, by Sunday afternoon you could see 20 to 40 cm of fresh snow in the Selkirks and smaller amounts further west. Accompanied by strong wind, this new snow will likely form touchy slabs.

At alpine and treeline elevations, a few layers of note are buried 40-80 cm deep including a layer of small surface hoar crystals on shady, wind-sheltered aspects and a series of crusts on solar aspects and below 1800 m. Overall the snow seems to be bonding well to these interfaces, although there have been a few isolated avalanches running on crusts layer over the past few days. Lower elevations have undergone daily melt-freeze cycles, with moist or crusty surfaces likely found up to at least 1800 m.

• Storm slab size and sensitivity to triggering will likely increase through the day.
• Dial back your terrain choices if you are seeing more than 25cm of new snow.
• Seek out sheltered terrain where new snow hasn't been wind-affected.
• The more the snow feels like a slurpy, the more likely loose wet avalanches will become.