Avalanche Forecast

Issued: Jan 28th, 2013 5:15PM

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

tim haggarty, Parks Canada

Waterton Lakes.

Be aware of the rapidly changing temperatures over the next few days especially if the sun comes out as the warming is occurring on Wed. Some great skiing can be enjoyed by riders that pay close attention to group management right now.

Summary

Weather Forecast

Expecting cold air to invade from the Prairies over the next two days. Warming should occur Wednesday. Winds look to remain out of the NW which usually translates to calm conditions below ridge crests in the Cameron Lake Zone. Mainly dry with clear breaks but expect a few flurries as warmer air West of the divide collides with the polar air.

Snowpack Summary

Now 30-40 cm over 130123 interface. On steep South aspects the 0125 suncrust is now buried 25cm and sits 15cm above the 0123 interface which is found as a 1cm thick suncrust with 10 to 20 cm faceted crystals below. On other aspects the 0123 interface is old settled windslab or faceted crystals. Windslabs forming on exposed ridges above treeline.

Avalanche Summary

Many loose snow avalanches have been seen out of extreme terrain on North and East aspects over the last few days. Skiers in steep terrain also experience sluffing. These have generally been slow moving but gain considerable mass. It can be particularly difficult to hold an edge on the hard old snow interface as a sluff starts to move.

Confidence

Problems

Loose Dry

Skiers in steep terrain should expect sluffing: slow but gain mass fast. This can be more serious where the old snow surface is very hard and it is difficult to hold an edge. Avoid confined features, pull off to the side, and do not ski above others.

Good group management is essential to manage current conditions safely.Avoid travelling on ledges and cliffs where sluffing may have severe consequences.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 2

Wind Slabs

Isolated windslabs can be found near exposed ridgecrests. These may be buried in places by a few cm. Probe for these with your poles and avoid steep or unsupported terrain where wind slabs exist especially if they overlie sun crusts or facets.

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

Possible

Expected Size

1 - 2

Cornices

These are large and appear to be quite fragile right now. Consider the loose snow or windslab avalanches these could trigger below them and manage your exposure accordingly. Particular caution as these experience rapid temperature changes Wednesday.

Extra caution needed around cornices with current conditions.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Jan 31st, 2013 4:00PM