Avalanche Forecast

Issued: Dec 17th, 2015 8:37AM

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

esharp, Avalanche Canada

South Columbia.

With plenty of low density snow already available for transport, wind will be the driver of avalanche danger tomorrow.

Summary

Confidence

Moderate - Wind speed and direction is uncertain

Weather Forecast

FRIDAY: the first wave of a series of weak storms is expected to hit bringing up to 10cm of new snow through the day, accompanied by light to moderate westerly winds, and a temperature at tree-line of -5C. SATURDAY: No precipitation is expected. Winds will continue to be light from the south and the tree-line temperature will creep up to -5C. SUNDAY: Up 5cm of snow, light to moderate south winds, -5C at tree-line.

Avalanche Summary

Avalanche activity appears to have tapered off since the weekend. Avalanche professionals in the field are reporting sluffing in steep terrain in response to skier traffic (aka good skiing). No new avalanches have been reported on the layer of buried surface hoar since last week, although this may be because people have been avoiding locations where it is likely to be found.

Snowpack Summary

It sounds like good riding conditions out there with mainly low density snow on the surface. Recent variable winds have produced small wind slabs on both south and north aspects. About 30 to 80cm of snow now sits above a crust that extends up to 1800m. The early December persistent weak layer can now be found down 40 to 120cm. This layer can be found as an old sun crust on solar aspects in the alpine, or as large grained surface hoar and small facets in isolated pockets below tree-line, especially between 1400m and 1800m. Snow pit tests on this interface have been widely variable; producing a mixture of sudden and resistant failures or no results. The mid and lower portions of the snowpack are thought to be mainly well settled.

Problems

Wind Slabs

Wind slabs are expected to develop at tree-line and in the alpine as the wind picks up through the day.

Avoid freshly wind loaded features and use ridges or ribs to sneak around these problem areas.>The recent snow may now be hiding windslabs that were easily visible before the snow fell.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Persistent Slabs

A layer of buried surface hoar can be found bellow tree-line, between 1400m and 1800m. It remains sensitive to human triggering. Watch out for signs of instability like wumphing to guide you through this elevation band.

Avoid open slopes, convex rolls, burns, cutblocks and terrain traps when traveling below tree-line. This is where buried surface hoar is best preserved and most volatile.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 4

Valid until: Dec 18th, 2015 2:00PM