On Saturday March 1 Bob Howell skied the upper part of the Libby Creek trail to the location given below for the snowpit. The weather was very nice, calm and partly sunny. The conditions on the trail were good, with a few inches of new snow from the previous couple nights. I met two other skiers on the trail. At 3 PM I dug a snow pit at NAD27 13T 0397575 4576871, elevation 10010 ft on an opening in the slope below the trail. This pit is about 40 ft NE of the pits dug on Dec. 7 and Nov. 17. This was a 16 deg. slope facing 140 deg (SE). The air temperature was -7C. The snow depth was 129 cm. The pit showed the following pack structure # Height Temp Layer comments Hardness Snow grain structure (cm) (C) air --- 129 ---------------------------------------------------------------------- 7 fresh snow fist 0.3mm dendritic crystals --- 126 ---------------------------------------------------------------------- 6 4 fingers 0.5mm dendritic, slightly rounded with slight crust at 6/7 interface --- 122 ---------------------------------------------------------------------- 120 -4.5 5 110 -5.0 1 finger 0.5mm slightly rounded 100 -5.0 ---- 97 ---------------------------------------------------------------------- 4 90 -4.5 1 finger 1.0mm faceted ---- 83 ---------------------------------------------------------------------- 80 -4.0 2 finger 1.5mm faceted 3 70 -3.5 There are several slightly harder icy 60 -2.5 layers within #3 ---- 58 ---------------------------------------------------------------------- 2 icy pencil 1.0mm rounded, welded ---- 56 ---------------------------------------------------------------------- 50 -2.5 40 -2.0 1 30 -1.5 depth hoar 4 fingers 4.0mm faceted 20 -1.0 10 -0.5 ----- 0 0.0 --------------------------------------------------------------ground Shovel shear test. Working down through the pack The fresh snow #6 and #7 slumped with very lightly force Moderately light force for failure at 4/5 interface (97 cm height) Moderately light force for failure within middle of layer #3 Easy shear once shovel penetrated to depth hoar layer #1 In the Rutschblock test the fresh layers #6 and #7 slumped when stepping on the block. A couple moderate jumps caused a well defined shear failure between layers #4 and #5. After that, repeated hard jumps just compressed the lower part of the pack. This last effect may be because of the low (16 deg.) slope and on a steeper slope the upper layers might well slide on the depth hoar. Summary: In the shovel shear and Rutschblock test the pack shows a significant shear weakness at the top of the faceted layer #4, 32 cm below the surface. The deep depth hoar also shows very little strength. When digging the snow pit, once you dig through about one half the pack, you simply collapse to the ground through the depth hoar. The pack here is significantly different than that measured on the Potholes trail two weeks earlier on Feb. 15. In the Potholes pit the depth hoar seems to be consolidating and hardening. That isn't the case here. Perhaps that is due to the south facing slope of this location (compared to the east facing slope for Potholes) and the presumably higher subsurface temperatures here. It could also be due to a different history of snow deposition as the pack is significantly deeper at the Potholes pit. The car counts were as follows. ------- 1 PM ------ with without trailers trailers Corner Mountain Lot 0 3 Little Laramie Lot 8 4 Below Ski Area Rd 5 0 Ski Area to Cattleguard 96 4 Cattleguard to Turnaround 24 10 Green Rock Picnic Gnd. Lot 0 6 P. G. to Snowy Range Lodge 36 9 Total 169 36