Archived

Avalanche Forecast

Feb 8th, 2015–Feb 9th, 2015

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

4: High

The avalanche danger rating at treeline will be high

Below Treeline

3: Considerable

The avalanche danger rating below treeline will be considerable

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

3: Considerable

The avalanche danger rating below treeline will be considerable

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

Regions: Banff Yoho Kootenay.

Very warm temperatures have weakened the snowpack and turned it isothermal in many locations. Avalanche terrain should be avoided until cooler temperatures return.

Weather Forecast

Cloudy with scattered flurries forecast for Monday. Freezing levels to valley floor on Sunday night and then rising to 2000 m on Monday. Winds are light from the south-west turning to moderate west late in the day on Monday.

Snowpack Summary

45 - 70 cm of recent storm overlies a crust from January 30th. The recent heavy precipitation, wind and warmer temperatures have created storm slabs which will put an enormous amount of stress on the January 30th crust interface. Isothermal conditions exist at treeline and below.

Avalanche Summary

Avalanche control today in Yoho Park and Koorenay Park produced numerous avalanches up to size 3. Many of the avalanches started dry and turned wet at lower elevations. Also, evidence of a widespread cycle up to size 3.5 throughout the forecast region. Some avalanches running close to full path.

Confidence

Avalanche Problems

Storm Slabs

Fifty to 90 cm of storm snow exist on the January 30th crust interface. A poor bond exists at this interface and large avalanches have been observed running on this layer.

If triggered the storm slabs may step down to deeper layers resulting in large avalanches.Avoid freshly wind loaded features.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Very Likely

Expected Size: 1 - 3

Loose Wet

Isothermal conditions exist at treeline and below. Many loose wet avalanches that have gouged down to ground have been observed below 1800 metres.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely - Very Likely

Expected Size: 2 - 4

Deep Persistent Slabs

The base of the snowpack remains weak due to basal depth hoar/facets. Additional snow load, or a storm slab failure may trigger large to very large avalanches in thin snowpack areas.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 2 - 4