Avalanche Forecast

Issued: Dec 17th, 2016 4:48PM

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

Ruari Macfarlane, Parks Canada

Waterton Lakes.

Change is in the winds! Wind Slabs should be obvious (when glimpsed through the blowing snow): avoidance is key. Avoidance of the outdoors might be another good strategy, with forecast winds in excess of 100 kph.

Summary

Weather Forecast

A return to a Westerly flow introduces a warming trend and extreme winds.Sun: Strong-Extreme Westerly winds. Cloudy. Temperature inversion. Rising temps at all elevations, with Treeline the coldest at -15.Mon: Extreme Westerly winds. 5-15cm of snowfall. -9 at Treeline.Tues: Moderate SW winds, -7 at Treeline, Light snowfall beginning.

Snowpack Summary

In Eastern areas, Strong winds have scoured slopes, or created hard Wind Slabs over facets. Closer to the divide, 25cm of soft snow is being blown into Wind Slabs on most lee slopes. Expect this to ramp up with extreme winds creating Wind Slabs low on slopes, and in other unusual places. These, and older wind slabs, overlie a faceted midpack.

Avalanche Summary

No new Natural avalanche activity has been observed since Wednesday.

Confidence

Timing, track, or intensity of incoming weather system is uncertain on Monday

Problems

Wind Slabs

The low density snow that has made for great skiing lately is being blown to many places. With Extreme winds, watch for Wind Slabs in unusual places. New snowfall on Monday will increase this problem. These may be hidden by more snowfall on Tuesday.

Be aware of the potential for wide propagations due to the presence of hard windslabs.Avoid steep lee and cross-loaded slopes

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

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Dec 20th, 2016 4:00PM