29 Nov 2012

Yesterday afternoon at 15:00 the front rolls up the valley.

As of 06:00 hrs at 2260 meters the temperature was -2, winds were 45-65 KPH from the SSE. At 1550 meters the temperature was 0. 8 cm of new snow was recorded at pig alley as of 05:30. In the valley it is +1.

Depending on which model you look at there could be 10-15 cm today. More snow on the way Friday, with as much as 25-30 cm. Confidence is low as most of the moisture is tracking south. Freezing level should hover around 1500 meters, dropping to 1300 tomorrow morning.

For the latest backcountry advisory: Advisory

Read the report from Dale Marcoux, Nov 27: ACMG Blog

CAC avalanche advisory: Advisory

Most of the precip is heading south: California

Snow observations from Mitch Sulkers, Lower Disease Ridge:




From Avalanche-centre.org, definition of bridging:

Bridging

The use of this term has been debated among professional avalanche workers, but it is commonly used to refer to a situation where a strong layer of snow lies over a weak layer, thus "bridging" it.
This is common mechanics problem in some ways, often called the "Simply Supported Beam with a point load". However, in the snowpack this bridge can be any length in any direction along the surface. The distance between supports is generally unknown. The material properties of the bridge material are poorly understood and often vary significantly throughout the bridge. And depending on how many people there are and how large the "bridge" is there may be multiple point loads.
So when the term "bridging" is used it implies a weak layer underneath a stronger layer which is at least somewhat supportable. The question of whether the bridging is consistently strong enough to be safe to travel on is a difficult one.

May not see this view for a while!!