South Columbia

New snow, wind, and warming temperature have created dangerous avalanches conditions. Stick to conservative low-angle terrain and avoid travel in the alpine.

• Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
• Make conservative terrain choices and avoid overhead hazard.
• Stick to well supported, lower angle terrain.
• Travel in alpine terrain is not recommended.

MONDAY NIGHT: Cloudy with scattered flurries bringing 5-10 cm of new snow, moderate to strong wind from the southwest, treeline temperatures around -4 C.

TUESDAY: Cloudy with scattered flurries bringing another 5-10 cm of snow, moderate wind from the southwest, treeline temperatures reach -2 C with freezing level climbing to 2000 m around Nelson and 1500 m around Revelstoke.

WEDNESDAY: Mostly cloudy skies, light wind from the south, treeline temperatures around -4 C with freezing level climbing to 1500 m.

THURSDAY: Mostly cloudy with scattered flurries bringing 5-15 cm of snow, light wind from the southwest, treeline temperatures around -6 C.

Reports from the beginning of the storm on Sunday suggest there were widespread natural and human triggered storm slabs across the region. They were mostly small (size 1) in the top 20 cm of new snow, although several size 2 natural avalanches were reported in the Selkirks.

We suspect larger storm slab avalanches occurred on Monday as the storm continued, and these slabs will remain reactive to human triggering on Tuesday.

Over the past week there have been daily reports of large (size 2 and 3) persistent slab avalanches in the Valhalla, Goat, and Kokanee Ranges. While many of the reports have been on north and east slopes, they have occurred on all aspects. The weak layers associated with these avalanches are currently being stressed by the weight of the new snow.

As the storm trails off on Tuesday expect a total of 30 to 50 cm of fresh snow. This snow sits above a variety of layers including heavily wind-affected surfaces on alpine slopes, sun crusts on steep south-facing slopes, and some feathery surface hoar crystal in sheltered areas. With mild temperatures and moderate wind in the forecast, expect to find reactive storm slabs at all elevations, with the most reactive slabs on freshly wind loaded slopes. Two potential weak layers exist within the upper snowpack: the mid-February layer (down 40 to 60 cm) and the late-January layer (down 100 cm). They both consist of surface hoar and/or melt-freeze crusts. Recent trends suggest these layers have been most reactive in southern parts of the region around the Valhallas, Kokanee, and Goat Ranges.