Avalanche Forecast

Issued: Feb 23rd, 2015 6:09PM

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

Tim Haggarty, Parks Canada

Waterton Lakes.

Watch out for fresh windslabs and be selective with your aspects to avoid solar crusts. Stability should improve with the expected cooling into the weekend.

Summary

Weather Forecast

More cloud development as a cold front pushes down from the NW should start to cool things by midday Tuesday and NW winds will continue.Â As the front passes midday Wednesday expectÂ up to 5cm of snow followed by the winds shifting to the West and abating. Cooling temperatures, lingering clouds and trace amounts of snow through Thursday and Friday.

Snowpack Summary

15cm fell on the weekend and NE and NW winds have redistributed this into windslabs on treeline ridgecrests and more widespread locations in the alpine. Surface crusts can be expected on steep SE through SW slopes. The Mid-December layer that is down over 1m in most deep areas remains a concern in high shaded terrain presenting a shallow snowpack.

Avalanche Summary

A few minor windslabs have been observed in the alpine that were likely triggered by continued wind loading. Pin-wheeling and minor loose wet avalanches occurred with heating yesterday and today on steep S and very steep E slopes and this activity may continue Tuesday morning with strong solar and an alpine temperature inversion possible.

Confidence

Problems

Wind Slabs

Fresh slabs can be found near ridgecrests at Treeline and in any lee features in the Alpine. Expect these to be sensitive to skier triggering especially while the temperatures remain warm Tuesday.

Use caution in lee areas. Recent wind loading have created wind slabs.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Loose Wet

Watch for the sun to rapidly warm the surface snow and cornices, raising the hazard Tuesday morning with lingering warm air at upper elevations and a weak freeze expected. This activity will become unlikely beyond Tuesday afternoon with cooling.

Do not travel on slopes that are exposed to cornices overhead.Avoid solar aspects.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Deep Persistent Slabs

Now 50 to 150cm deep these slabs continue to stand out as a concern in the TL and ALP areas where there is not a strong Jan 31 crust over them (2200m+). Be particularly mindful in thin snowpack areas where this layer is more likely to be triggered.

Be aware of thin areas that may propogate to deeper instabilites.Carefully evaluate and use caution around thin snowpack areas.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Feb 26th, 2015 4:00PM