Archived

Avalanche Forecast

Feb 3rd, 2019–Feb 4th, 2019

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Banff Yoho Kootenay.

Increased reactivity of the Jan 17 surface hoar/crust layer is due to recent loading of storm snow. Distribution is spotty, so dig down to verify if this layer is present in your local area.

Weather Forecast

Thankfully, today is forecasted to be the coldest day. Temperatures will climb back to a somewhat reasonable level by tomorrow to about the -18 range in the valley. A clearing trend will ensue, and the wind will drop back to light from the West. No snow is forecasted for a while.

Snowpack Summary

30-45cm of recent storm snow is being redistributed into windslabs above treeline. Up to 65cm sits over the Jan.17 surface hoar which has been found up to 2300m. In shallower areas weak facets and depth hoar exist below the Dec 10 interface. In deeper snowpack this basal weaknesses is less pronounced

Avalanche Summary

No avalanches reported or observed today, however yesterday there were two skier accidental avalanches size 1.5. One was on Vermillion Peak (reported on the MIN) the other was at Bow Summit. Both were suspected to have slid on the Jan 17 Surface Hoar. No injuries or lost gear in either slide.

Confidence

Due to the number of field observations on Sunday

Avalanche Problems

Wind Slabs

Wind was observed redistributing the recent storm snow in the alpine and creating fresh windslabs in lee areas. These slabs could be up to 70cm deep. For clarity, the storm slab problem has transitioned into the windslab problem.

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

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

Elevations: Alpine.

Likelihood: Likely

Expected Size: 1 - 2.5

Persistent Slabs

The Jan 17 layer is a combination of Surface Hoar and/or a melt freeze crust. Since the recent storm, it has become reactive to skier traffic and can generally be found down 50cm. Dig down, look and test this layer at tree line and below.

Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 2

Deep Persistent Slabs

The new snow load may start waking up the deep persistent facet weakness down 80-160 cm. This is of greatest concern in shallow snowpack areas where the basal facets are weakest.

Avoid thin, rocky or unsupported slopes.

Aspects: All aspects.

Elevations: Alpine.

Likelihood: Unlikely - Possible

Expected Size: 2 - 3