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Avalanche Forecast

Jan 9th, 2014–Jan 10th, 2014
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
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
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

Fair - Timing, track, or intensity of incoming weather system is uncertain on Saturday

Weather Forecast

Friday:  5 to 10 cm of precipitation for Friday, winds from the west up to 50 km/h with freezing levels rising to 1000 m.Saturday:  10 to 20 cm of precipitation, strong southwesterly winds, freezing level may rise to 1300 m as a pacific frontal system moves through the rockies.Sunday:  Isolated flurries in the wake of the storm system, freezing levels drop to valley bottom, continued strong winds from the southwest.

Avalanche Summary

Windslabs were triggered by a vehicle and by explosive control in the Eastern part of the region on an E facing aspect slopes. These avalanches were up to 1.5 in size and would have slid on older faceted surface or on low density new snow. A detailed incident report about the Corbin area near miss is available here.

Snowpack Summary

Windslabs continue to develop on lee slopes at ridge tops and in the alpine. The recent storm slabs are settling but may still be sensitive to human triggers, especially where a weak faceted snowpack is underlying the top  layer. The facet/crust layer down 80-100 cm at treeline and below treeline and the depth hoar layer in the alpine has been  reactive on E aspects. Recent natural and human triggered avalanches on this aspect are a good sign of this instability. When tested and observed, the surface hoar layer down 70 cm is showing signs of healing (grains are rounding and snowpack tests are not as planar as they have been previously). The South Rockies field team has posted a new blog with some good info and pictures about the recent avalanche incident and about current conditions. Click here to read it.

Avalanche Problems

Wind Slabs

New storm snow will contribute to the existing wind slab problem and will remain a problem for some time.
Avoid exposure to terrain traps where the consequences of smaller avalanches could be serious.>The recent snow may now be hiding windslabs that were easily visible before the snow fell.>Be extra cautious in steep lee and cross-loaded features>

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

Elevations: Alpine.

Likelihood: Possible

Expected Size: 1 - 4

Persistent Slabs

Avoid open slopes and convex rolls at and below treeline where the crust/facet combo or depth hoar exist.>Dig down to find and test weak layers before committing to a line.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 3 - 6