Avalanche Forecast

Issued: Mar 11th, 2016 8:27AM

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

ccampbell, Avalanche Canada

South Rockies.

Unsettled weather is expected to keep avalanche danger elevated, especially at higher elevations in exposed terrain.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Saturday

Weather Forecast

SATURDAY Mainly cloudy with isolated light flurries possible, except east of the divide where it is expected to remain mostly clear. Freezing levels hovering around 2000m and moderate to strong southwesterly ridgetop winds. SUNDAY: Mainly sunny with cloudy periods, isolated light flurries possible with freezing levels dropping back down to 1700m and moderate to strong southwesterly ridgetop winds. MONDAY: A mix of sun and cloud, isolated light flurries possible with freezing levels remaining near valley bottoms and moderate to strong southwesterly ridgetop winds.

Avalanche Summary

Reports from Thursday are limited but include skier-controlled Size 1 fresh wind slab avalanches. Natural wind and storm slab avalanche activity was expected on Thursday in response to heavy loading from snow, wind and rain. On Friday, intense sun-exposure could trigger another round of natural activity, including large cornice falls potentially triggering deeper persistent slabs.

Snowpack Summary

Approximately 20cm of fresh snow is bonding poorly to a widespread supportive crust, with the most recent snowline reaching 1800m in the Elk Valley but remained in valley bottoms overnight. In exposed terrain, widespread very touchy wind slabs lurk below ridgecrests, behind terrain breaks and in chutes. Deeper in the snowpack, recent tests gave very easy sudden collapse results down 80cm on a southeast aspect at 1850m on the deep persistent facet/crust weakness from buried early December. Watch this weakness with extreme warming from sun-exposure, or warming/loading from rain. Cornices are also reported to be huge and weak. Check out the latest SoRo field team video on our Avalanche Canada Instagram site!

Problems

Storm Slabs

Recent storm snow is bonding poorly to a buried crust and particularly deep and touchy on wind-loaded slopes.

Use ridges or ribs to avoid pockets of wind loaded snow.>The new snow will require several days to settle and stabilize.>Be cautious as you transition into wind affected terrain.>Minimize exposure to sun exposed slopes when the solar radiation is strong.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 3

Cornices

Continued warm temperatures and wind-loading will keep large droopy cornices weak. Not only are massive cornice falls a hazard in themselves, but they can also act a heavy trigger for slab avalanches on the slope below.

Give cornices a wide berth when travelling on or below ridges.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 5

Valid until: Mar 12th, 2016 2:00PM