Avalanche Forecast

Issued: Mar 7th, 2018 5:17PM

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

Avalanche Canada shorton, Avalanche Canada

Danger will increase late on Thursday and into Friday as new snow accumulates.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain on Thursday

Weather Forecast

THURSDAY: Flurries increasing throughout the day with up to 5 cm in the north and up to 10 cm in the south, moderate south wind, freezing level rising to around 1500 m.FRIDAY: Another 10-20 cm of snow and then clearing in the afternoon, light wind, freezing level dropping to around 1000 m.SATURDAY: Mostly sunny with freezing level rising to around 1600 m.

Avalanche Summary

Numerous loose wet avalanches were observed in steep south-facing terrain on Wednesday and Tuesday. Most were small (size 1), but a few in the Coquihalla reached size 2.Last weekend, a few size 2 natural slab avalanches were reported in the northern part of the region on a range of aspects around 2000 m.

Snowpack Summary

New snow will accumulate on Thursday and Friday and form extra deep deposits in wind loaded terrain. The new snow is falling on a sun crust on steep south-facing slopes, cold dry snow on polar aspects, and wind affected snow at upper elevations.In northern parts of the region the mid-February weak layer is about 40 cm below the surface and has been reactive in some snowpack tests. The layer is composed of sugary facets, a sun crust on solar aspects, and surface hoar that is present at and below treeline. No recent avalanche activity has been reported on these layers.The snowpack is well settled in southern parts of the region (e.g. Coquihalla and Manning Park).Variable winds in the past month have created cornices on many alpine ridgelines. They will become touchier as they grow in size, as temperatures rise, and as the strong late-winter sun shines down upon them on clear days.

Problems

Wind Slabs

An icon showing Wind Slabs
Fresh wind slabs will build throughout the day at higher elevations.
Minimize exposure during periods of heavy loading from new snow and wind.Use ridges or ribs to avoid pockets of wind loaded snow.Use caution on open slopes and convex rolls

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Cornices

An icon showing Cornices
Cornices are inherently unstable, unpredictable, and demand respect. New snow and warming will likely make cornices extra brittle.
Give cornices a wide berth when travelling on or below ridges.Watch out for overhead hazards, such as cornices, which could trigger slabs on slopes below.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2.5

Valid until: Mar 8th, 2018 2:00PM