Avalanche Forecast

Issued: Jan 2nd, 2014 4:00PM

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

tim haggarty, Parks Canada

Waterton Lakes.

Active weather for the period could increase hazard. Watch the local snowfall amounts and winds carefully. Rapid loading could wake up deep persistent slabs. Remember that early season hazards remain a serious concern.

Summary

Weather Forecast

We are expecting snow Friday morning provided by the current Westerly flow. The competing arctic high over the prairies will take over after this invading from the North with a steady cooling trend to the -20C range by Sunday. Precip amounts are uncertain but may be locally significant if the arctic air holds the warm moist air against the divide.

Snowpack Summary

Generally a thin and weak snowpack averaging 1m near treeline. West winds have strongly influenced coverage: scouring windward areas leaving windslabs near ridgelines and in gully features. Thin suncrusts have formed on South aspects as high as 2200m. Weak faceted snow that can be found 30 to 40 cm above the ground remains a concern in thin areas.

Avalanche Summary

There has been no activity in the last few days.

Confidence

Forecast snowfall amounts are uncertain

Problems

Wind Slabs

Hard surface slabs are found near ridge crests and in gully features. These are highly variable at the moment with suspect pockets in steep and unsupported terrain.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Be cautious as you transition into wind affected terrain.

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

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

Weak faceted or sugary snow can be found almost everywhere 30 to 40 cm above the ground. Triggering in thin snowpack areas remains a concern. Some natural avalanche activity should be expected if snowfall amounts are significant Friday.

Dig down to find and test weak layers before committing to a line.Minimize exposure during periods of heavy loading from new snow, wind.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 3

Storm Slabs

The incoming snow will cover a variety of firm surfaces including the windslabs described above, wind affected surfaces, and sun crusts on S aspects. West winds and mild temperatures are likely to encourage slab formation in specific areas.

The new snow will require several days to settle and stabilize.Choose conservative lines and watch for clues of instability.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Jan 5th, 2014 4:00PM