South Columbia

Forecast new snow amounts are uncertain. Watch for developing hazard due to new snow and wind.

Moderate - Timing, track, or intensity of incoming weather system is uncertain

Overcast with light snow, light northwest winds, and freezing levels down to 800 metres overnight. Light snow with increasing southwest winds on Wednesday and daytime freezing levels up to 1800 metres. Moderate precipitation (10-15 cm) starting early Thursday with moderate to strong southwest winds and overnight freezing levels around 1300 metres. Freezing dropping back to valley bottoms by Friday morning. A weak ridge is expected to build on Friday, but we are un-certain regarding the amount of sunshine we will see.

No new reports of persistent slab avalanches on Monday. Loose wet solar induced activity in most areas up to size to size 2.0, as well as some thin wind slabs in the high alpine on shaded aspects. On Sunday we had reports of natural cornice falls up to size 3.0 that triggered persistent slab avalanches on the slopes below, and solar triggered persistent slab avalanches up to size 2.5 in the alpine from slopes steeper than 40 degrees. On Saturday cornice fall produced avalanches to size 3 on north and northeast facing features between 2000 and 2400 m, failing on the late February persistent weak layer. Small natural storm and wind slabs were also reported on northwest, northeast and east facing slopes between 2100 and 2400 m.

Freeze and thaw conditions have developed a crust on solar aspects at all elevations, and up to at least 2000 metres on shaded aspects. Recent storm snow has released as loose wet avalanches on steep solar aspects. Cornices continue to be described as large and fragile. The make up of the late February persistent weak layer is an aspect dependant mix of surface hoar, facets and/or a thick crust down around 60 to 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. Forecast new snow may not bond well to hard crusts on solar aspects, and pockets of wind transported snow may develop in the alpine and at treeline. Wind transported snow may trigger fragile cornices.