29 Dec 2012

An exciting morning December 28, 2012. A snow cat released a size 2.5 avalanche on a slope referred to as Prime Rib. The weight of the cat, 8,400 Kg created a slide on the November 4 Th crust, which has been dormant for 4 weeks. The cat road was extended the previous evening and created an area about 1 meter deep in the 2.5meter snow pack allowing the weight of the cat to fail on the rounded facets in the November 4 crust, stepping down to the summer firn on this slope.  No one was hurt and the snow cat drove away after a brief slide down the incline.

The crown was 2.4 meters deep, about 120 meters wide and was on average 2 meters thick from side to side.

 The trigger point was just right of Tony.

 At 2260 meters the temperature was -7, winds were 10-20 KPH from the S. At 1650 meters 3 cm of new snow fell over night and the temperature was - 3.5. In the valley it was -3. Observations were taken electronically as of 06:00 Hrs.

For the forecast expect unsettled conditions this morning with sun in the afternoon. A ridge of high pressure will eventually establish it self this afternoon and continue through until Early Friday morning when hopefully we will be back into a snow cycle.

For the updated local avalanche advisory: Blackcomb Snow Safety Advisory

Some interesting facts and a video from the live recovery from Crystal Mountain: Lucky lady

6 tips for surviving an avalanche, their perspective: The CLYMB

Questions raised about Donner Ski Ranch Avalanche: News 10

Canadian Avalanche Centre's On line Avalanche Course: Powder Canada

Current Backcountry Dangers High around Vail : Vail Daily

Avalanche in Lower Dir; two people buried: Pak-Afghan Border

Ski Patrollers get airbags: Vail Resorts

The crust which is about 40 cm above the summer firn. Two thin and brittle ice crusts that sandwiched a variable hand hardness layer of 4f to P, 3-5 cm thick 1 mm FCxr (rounding facet) crystals.

The grousers marks  from the cats tracks are evident in the ice.

A winch cat weighs 8,400 Kg.