Avalanche Forecast

Issued: Feb 28th, 2017 4:00PM

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

aaron beardmore, Parks Canada

Banff Yoho Kootenay.

Wind, snow and warmer temperatures are expected between today and the end of the week. Expect the danger rating to rise.

Summary

Weather Forecast

The forecast region is expecting an increase in wind velocity from the west starting Tuesday evening, accompanied by light snowfall that will carry through until Wednesday morning. Temperatures will slowly rise to the -5 range at valley bottom in the same time period. A second wave of precip will track through the forecast region late on Friday.

Snowpack Summary

There is 15-25 cm of low density snow at tree line with a thin rain-crust below the storm snow at lower elevations. Some wind effect exists in alpine areas and it is expected to increase. 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 Tuesday.

Confidence

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

Problems

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. A failure can propagate to deeper areas and cause large avalanches.

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

Unlikely - Possible

Expected Size

2 - 3

Wind Slabs

West wind (mod to strong) and light snowfall amounts will create wind-slabs in lee areas at tree-line and above starting Tuesday evening. There is uncertainty as to how touchy these slabs will be.

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

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Mar 1st, 2017 4:00PM