Avalanche Forecast

Issued: Dec 28th, 2015 8:11AM

The alpine rating is moderate, the treeline rating is low, and the below treeline rating is low. Known problems include Wind Slabs.

Avalanche Canada triley, Avalanche Canada

These danger ratings reflect the conditions in most of this region. A report from the southern Monashees around Big White indicate that conditions may be quite different and these danger ratings may be too low for that area.

Summary

Confidence

Moderate - Wind effect is extremely variable

Weather Forecast

Overcast with light snow overnight and Tuesday resulting in a total of 3-5 cm and light northeast winds. Freezing level will remain at valley bottoms throughout the forecast period. Gradual clearing on Wednesday with light northerly winds. Clear on Thursday with valley cloud as an inversion develops above freezing temperatures in the alpine and traps cooler air in the valleys. The inversion may not develop until Friday.

Avalanche Summary

There is a great deal of variability across the region. The southern Monashees have reported 40 cm deep soft slabs that are easy to trigger and likely to entrain loose dry snow in avalanche tracks and runouts. As you move east across the region the storm slab depths become less, with about 20 cm in the Rossland range, and closer to 10 cm of recent snow 40-50 cm of overall storm snow in the Kootenay pass.

Snowpack Summary

The southern Monashees around Big White have reported recent storm slabs up to 40 cms that are easy to trigger. Another 5-10 cm of new snow fell on Sunday in the Kootenays, making the weekend total about 10-20 cm of dry cold snow. This snow fell on a variety of old surfaces including small grain facets, surface hoar up to 14mm in size and a sun crust on steep south and southwest facing features. In the last week the region received 40 to 60cm of storm snow that remains largely unconsolidated. Below this snow you will find the mid-December crust. It has not been problematic anywhere yet, but in Kootenay Pass there is a spotty surface hoar layer on or just above this crust. This interface is down around 60cm and the surface hoar is most prevalent on north facing features between 1800 and 2000m. At treeline the early December crust is down around 70 to 120cm. This thick and supportive crust is likely capping any deeper weaknesses in most places. There have been reports of facets on this crust in the Nelson area, so we'll want to keep our eye on it as we move into the New Year. The lower snowpack is thought to be well settled.

Problems

Wind Slabs

An icon showing Wind Slabs
Deep pockets of wind transported snow may continue to be easily triggered. This problem may be more pronounced in the West of the region in the southern Monashees.
Exercise extra caution around recently wind loaded features and use ridges/ribs to sneak around these problem areas.>Extra caution needed around cornices with current conditions.>

Aspects: North, North East, East, South East, South.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Dec 29th, 2015 2:00PM

Login