Archived

Avalanche Forecast

Feb 22nd, 2013–Feb 23rd, 2013

Alpine

4: High

The avalanche danger rating in the alpine will be high

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

3: Considerable

The avalanche danger rating at treeline will be considerable

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

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: South Rockies.

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain for the entire period

Weather Forecast

Friday night/Saturday: Extreme W winds easing to moderate overnight and switching to moderate to strong NW on Saturday. Moderate snowfall overnight, easing to light on Saturday. Alpine temperature around -10.Sunday: Strong W winds. Light snow. Alpine temperature around -7.Monday: Light SW winds. Light to moderate snow. Alpine temperature around -10.

Avalanche Summary

Loose dry avalanches (size 1) have been failing naturally and with skier traffic in steep terrain. I expect the size and frequency of avalanches has increased on Friday, and activity to continue through the weekend.

Snowpack Summary

By Saturday morning, I expect there might be up to 70 cm accumulated recent snow. Snowfall started light and dry this week, and may be easily shifted onto lee slopes by strong W to NW winds. New storm slabs, cornices and wind slabs are likely. Mostly this snow overlies loose dry surfaces, old wind slabs below ridge crests, and sun crusts on solar aspects. A surface hoar/facet/sun crust layer from mid February (12th) may be buried in the upper snowpack, but it has not been widely reported from this region. Mid and lower snowpack layers are generally well settled and stable.

Avalanche Problems

Storm Slabs

Loading from new snow and wind will rapidly increase avalanche danger, particularly on wind-loaded slopes.

Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>Stick to non-avalanche terrain or small features with limited consequence.>Be aware of what is above you at all times.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Very Likely

Expected Size: 2 - 5