Avalanche Forecast

Issued: Dec 14th, 2016 3:19PM

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

Avalanche Canada rbuhler, Avalanche Canada

Wind slabs continue to be the primary concern. Watch for signs of recent wind loading and use extra caution in wind exposed terrain.

Summary

Confidence

Moderate - Wind speed and direction is uncertain

Weather Forecast

The cold Arctic air is expected to persist through the weekend. On Thursday, mostly cloudy conditions are expected with treeline temperatures around -15C and moderate outflow winds in the valleys. There is a chance of light flurries on Thursday in the south of the region. Friday and Saturday are currently expected to be mainly sunny with light to moderate alpine winds and treeline temperatures below -20C.

Avalanche Summary

On Tuesday, natural size 1 wind slab avalanches were reported in alpine terrain. One snowmobile triggered size 1 wind slab avalanche was also reported. This was intentionally triggered on a loaded convex roll. On Thursday, wind slabs are expected to remain reactive to human triggering in exposed terrain at treeline and in the alpine. With ongoing moderate outflow winds forecast, these wind slabs are expected to continue to build.

Snowpack Summary

Up to 30 cm of low density storm snow from the weekend is being redistributed into soft slabs in wind exposed terrain. The new snow is sitting on top of a mixture of surface hoar and weak surface facets which means the storm snow could become reactive when it settles into a slab. The mid pack is reported to be well settled. Reports suggest typical treeline snow depths are around 120-170 cm, but a report from the east side of region indicated a much lower snow depth of around 90 cm. Limited reports suggest the snow is well bonded to the crusts buried in mid and early November which are down 50-80 cm and 80-110 cm, respectively.

Problems

Wind Slabs

An icon showing Wind Slabs
Recently formed wind slabs are reported to be reactive to triggering in exposed terrain. Ongoing outflow winds will continue to build these slabs. Watch for signs of recent wind transport and avoid areas where the surface snow feels stiff.
Use ridges or ribs to avoid pockets of wind loaded snow.Be cautious as you transition into wind affected terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Dec 15th, 2016 2:00PM