Detailed Observation

ObserverGareth Brown

General Observations

Girls mountain up to 5000'. SE-SW aspects, -10° F at the road, 0°F at 3000' and above.  Light winds at the road becoming strong as you moved up in elevation.  Snow surface consisted of varying degrees of wind effect, with areas of protected powder.

Dug two pits today in similar locations 3200', SE aspect, 25° slope, light winds.  The first in an area where the storm snow was deep and in another where it was thin.  The first pit had a 280 cm depth, with 125 cms of settled storm snow.  Stability test produced ECTN21 down 30, with no reaction on the 12/9 rain crust buried 125 cms deep.  Also performed a deep tap test on the same layer with no result DTN.  

In a second pit in a similar location found the 12/9 crust buried 45 cms down.  Stability tests produced ECTP30 down 45cms.

These results indicate that the 12/9 rain crust is gaining strength in this location.  In places where the weak layer is closer to the surface this weak layer still showed signs of propogation, which required a lot of force to initiate. The ability is still there to trigger large avalanches from thinner areas of the snowpack.  This could be caused by a snowmachines' track digging into deeper layers of the snowpack, multiple people on slope, cornice fall, any other large load, or simply finding the sweet spot.  

Above 4000' experienced moderate to intense snow transport from north wind.  


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