Avalanche Forecast

Issued: Mar 2nd, 2017 4:00PM

The alpine rating is high, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Wind Slabs, Deep Persistent Slabs and Loose Dry.

stephen holeczi, Parks Canada

Banff Yoho Kootenay.

A short intense storm is currently forecast for Friday. Expect increasing danger throughout the day, peaking Friday night. Stick to very conservative terrain and avoid overhead exposure until after the storm has abated. SH

Summary

Weather Forecast

A 24 hour long system will roll into the region Friday AM with 3000m winds up to 100kmh, 2000m winds around 40kmh and 20-30cm of snow. Temperatures will be around -10C in the alpine and -3 to -5C at 2000m. Winds will die down and temperatures will cool off Saturday and Sunday.

Snowpack Summary

There is variable amount of wind slab development at tree line and above. Below 1850m a thin rain-crust sits below 10-15cm of recent snow. Common throughout the region are the weak facets and depth hoar in the lower half of the snowpack, overlain by a 40-60 cm slab of well settled snow.

Avalanche Summary

No new avalanche activity was observed or reported on Wednesday.

Confidence

Forecast snowfall amounts are uncertain on Friday

Problems

Wind Slabs

With increased load and strong to extreme winds, expect rapid wind loading and failure of new wind slabs. These may be enough of a trigger in certain places to step down to deep persistent layers causing bigger avalanches.

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

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Deep Persistent Slabs

There is a thick slab over a structurally weak snowpack in most areas. Avoid thin parts of a slope or rocky outcrops at tree line and above. We may see increased natural activity through the storm on Friday and Saturday.

Use conservative route selection, choose moderate angled and supported terrain with low consequence.Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 3

Loose Dry

In the short term, expect heavy sloughing in alpine gullies and avoid overhead hazard.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 2

Valid until: Mar 3rd, 2017 4:00PM