Avalanche Forecast

Issued: Dec 24th, 2014 4:00PM

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

jon stuart-smith, Parks Canada

Waterton Lakes.

The new snow is a welcome sight after the recent warm weather but has also increased the avalanche danger. Weak layers including surface hoar along with wind slabs are hiding under this blanket. The snowpack is still shallow below treeline.

Summary

Weather Forecast

Cooler compared to the last while with highs forecast to be -10 at Akamina Pass for the next few days. Winds will pick up again from the west starting Thursdays and there is now a lot of snow for transport. Another storm is forecast to arrive late Saturday with another 5-10cm and strong west winds.

Snowpack Summary

20-25cm of fresh light snow overnight and this morning, which means there is now 40 to 60cm of storm snow at treeline over the last week. This is sitting on the weak layer of facet crystals capped with isolated pockets of surface hoar which is overtop the Dec 13 crust. Strong west winds have built significant slabs in alpine features

Avalanche Summary

No new avalanche activity was seen on Wednesday but visibility was poor with the incoming storm. There has likely been some activity on steep terrain in the alpine.

Confidence

Due to the number of field observations

Problems

Storm Slabs

The weak snow above the crust is new primed with a big enough slab for there to be serious consequences of triggering an avalanche. Isolated areas that hold surface hoar should be treated with even more respect.

Dig down to find and test weak layers before committing to a line.The new snow will require several days to settle and stabilize.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Wind Slabs

The storm snow may now be hiding wind slabs in the lee areas of exposed features above treeline. New slabs will build with the 20-25cm of storm snow now available for transport. These will become larger and more easily triggered as the wind picks up.

Be cautious as you transition into wind affected terrain.The recent snow may now be hiding windslabs that were easily visible before the snow fell.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Dec 27th, 2014 4:00PM