On Sunday Feb. 20 Bob Howell was in the Green Rock area with the NSP Avalanche class 
being conducted by Frank Davis and others.   The temperature was in the upper 20's, 
it was partly cloudy with some light snow showers towards afternoon, and the wind 
was mostly calm.  Trail conditions were good, and the snow stake at the start of 
the Libby Creek trail showed 45 inches.  Beyond the participants and instructors 
in the Avalanche Course, several other skiers came through the area.

The following snow condition report is a summary of the results obtained by 
Myron Allen, Neil Mathison, and others as part of the course activities.  
The snow pit was at UTM location 0397928 4577663 (NAD 27), elevation 9880 ft, 
in a moderate opening in the trees on a 30 degree slope facing azimuth 80 (ENE).  
This is in the drainage leading from Green Rock up to a couple lakes in the 
Natural Area.


 layer height   Hardness      Crystal structure             Notes
   #   cm     
------ 125 ---------------------------------------------------------------------
   4             fist         rounded needles < 1mm    relatively fresh powder
------ 115 ---------------------------------------------------------------------
   3             fist         rounded  < 1mm           older powder
------  90 ---------------------------------------------------------------------
                                                       horizontally discontinuous
   2             1 finger     more rounded < 1mm       might be old buried
                                                       ski tracks
------  75 ---------------------------------------------------------------------
   1             four finger  faceted   2mm at depth   partially consolidated
                                       smaller above   depth hoar
------   0 ---------------------------------------------------------------------

There was little structure evident in the pack beyond the slight boundary between the 
two "fresh" upper layers, and the possible old ski tracks near the top of the depth hoar.
There were not any obvious divisions in the depth hoar but there was a gradual change in crystal size.

In a shovel shear test it required slight to moderate force to cause a shear near the bottom of layer 3,
then moderate force to cause a failure at ground level.  In a compression test dropping a 10 lb
snow filled stuff sack, a drop of 15 cm caused slight shear in the upper layers, then a 
drop of 35 cm caused complete failure near ground level.

On a Rutschblock test, the pack failed on "6", that is, on a second moderate jump, near the top of layer 1.

The car counts were as follows:

                          At 7:30 AM                 At 2:30 PM

                            with    without         with    without
                          trailers  trailers      trailers  trailers
 Corner Mountain Lot          0         1            0         1
 Little Laramie Lot           0         0            0         1
 Below Cattleguard            2         0           50         2
 Cattleguard to Turnaround   12         0           20         4
 Green Rock Picnic Gnd. Lot  --        --            0        19
 P. G. to Snowy Range Lodge  --        --           29         7

 Total                       --        --           99        34