Archived

Avalanche Forecast

Dec 7th, 2012–Dec 8th, 2012

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

1: Low

The avalanche danger rating below treeline will be low

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

1: Low

The avalanche danger rating below treeline will be low

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

1: Low

The avalanche danger rating below treeline will be low

Regions: South Rockies.

Confidence

Poor - Due to limited field observations

Weather Forecast

Overnight and Saturday: Light to locally moderate snowfall on Friday night with clearing on Saturday / moderate northwest winds becoming light and northwest with clearing / Freezing level at surfaceSunday: Light snowfall / moderate northwest winds with extreme gusts / Freezing level at surfaceMonday: Light snowfall / moderate southwest winds / Freezing level at surface

Avalanche Summary

No recent avalanche observations.

Snowpack Summary

Recent storm accumulations have been highly variable throughout the region; however, some ares saw significant snowfall earlier in the week. In general, winds have been moderate to strong creating widespread windslabs at higher elevations, although I suspect that in recent days they may have gained some strength. In some areas the most recent accumulations may sit over a rain crust that extends up to 2000m. There have been reports of buried surface hoar up to a metre down. This layer, which was buried at the end of November, seems most prevalent on the west side of the region. Little is known about its current reactivity.At the base of the snowpack you may find the early November crust which is associated with a layer of facets either directly above or below. Recent tests have shown sudden results at this interface.In general, snowpack data is sparse in this region and significant variations likely exist from one drainage to another. Digging down and making your own observations will be critical to safe slope selection. Any observations from the field are welcome at [email protected].

Avalanche Problems

Wind Slabs

Significant snowfall and winds from earlier in the week have created new wind slabs. Watch for triggering in gullies, below ridgecrests and behind terrain features

Be cautious as you transition into wind affected terrain.>Be alert to conditions that change with elevation.>Avoid travelling in areas that have been reverse loaded by winds.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 4

Deep Persistent Slabs

We have not heard of any new releases on this early season rain crust; however, an avalanche at this interface could be surprisingly large and destructive.

Be aware of the potential for full depth avalanches due to deeply buried weak layers.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 1 - 5