Avalanche Forecast

Issued: Feb 2nd, 2015 4:00PM

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

tim haggarty, Parks Canada

Waterton Lakes.

While hard crusts have allowed for interesting travel in the last few days, travel on steep slopes has been tough with out ski crampons or even an ice axe and crampons. Watch forecasts closely for Thursday and the weekend: Pineapple headed our way.

Summary

Weather Forecast

Not much change can be expected Tuesday or Wednesday with continued flurries and freezing levels below 1600m. Thursday however, a fairly powerful low reaches the coast straight from Hawaii... freezing levels are expected to approach 2000m with heavy precip and strong winds. Hopefully the arctic air on the prairies pushes back to keep temps low.

Snowpack Summary

West winds have created new windslabs above the Jan 31 crusts that extend nearly every where except on shaded aspects above 2300m. Above 2000m on the shaded aspects concern for the Dec facets and crust layer remains with technicians still finding sudden shears down 40 to 80cm. Hard crusts are the dominant travel condition: bring your ski crampons!

Avalanche Summary

Technicians traveling near the divide today found new windslabs above the hard crust to be sensitive to ski cutting. Otherwise, no activity has been seen in the last few days since the snow refroze after last week's warm up.

Confidence

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

Problems

Wind Slabs

New windslabs are quickly forming as the West winds push around what little snow has fallen. The bond to the hard crust below seems poor. Use caution: even a small avalanche could push you a long distance over the hard crusts that exist right now.

Avoid freshly wind loaded features.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Persistent Slabs

Now 40 to 120cm deep these slabs continue to stand out as a real concern in the TL and ALP areas that do not have strong surface crusts. Be particularly mindful in thin snowpack areas where this layer is more likely to be triggered.

Dig down to find and test weak layers before committing to a line.If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Storm Slabs

The pineapple forecast for Thursday will change things in a hurry: with warm temps and strong winds, expect rapid slab formation TL and above. With a freezing level of 2000m expect loose wet, or thin wet slab activity BTL.

The new snow will require several days to settle and stabilize.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Feb 5th, 2015 4:00PM