Avalanche Forecast

Issued: Mar 9th, 2018 4:13PM

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

Lisa Paulson, Parks Canada

Banff Yoho Kootenay.

This is our first big warmup - the hazard will be Low in the morning and rise to Considerable on solar aspects. Northern aspects will stay at a lower hazard. Cornices overhead may start to fail, and could potentially trigger deeper layers.

Summary

Weather Forecast

Our first major warming trend will occur over the next several days. Expect sunny skies and temperatures to get incrementally warmer with each day, peaking on Tuesday/Wednesday. For Saturday, expect treeline highs to be around -3C, winds light from the SW and freezing levels to be around 1600 m.

Snowpack Summary

Last weeks storm of 10-25 cm sits on a supportive midpack. The surface snow has had some wind transport in the alpine forming thin wind slabs .A sun crust has formed on solar aspects at treeline and below. The deeper facet layers down 80-150 cm remain weak and are currently dormant, but could become active with the warm days ahead.

Avalanche Summary

On Friday, there was a skier involvement in a size 1.5 windslab avalanche (30-40 cm thick, 50 m wide, ran 200m) on a lee slope above Bow Summit. Also noted were some loose wet avalanches to size 1.5 caused by the sun in steep rocky terrain below treeline.

Confidence

Problems

Wind Slabs

Alpine West winds have formed wind slabs in lee areas near ridge crests over the past week. In steep unsupported terrain skier triggering is possible.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 1.5

Loose Wet

Expect loose wet avalanches to initiate from steep rocky terrain. Watch for increasing hazard associated with prolonged sun affect.

Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.

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

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 2

Valid until: Mar 10th, 2018 4:00PM