OCR Text |
Show 2 Plot No. 1 - This is the control plot and for its whole depth it offered very little resistance to the penetrometer. This indicates a weak snow mass from top to bottom. This type of profile will usually support a skier, due to the planing properties of the ski, under high speed travel. However, if the skier slows down or stops, floatation is extremely poor and the skis break through the whole mass until the ground is reached. Plot No. 2 - Shows how the resistance was increased by sidestepping on skis with one pass across the plot. The top few inches of snow increases in resistance due to disturbance and age hardening. The center of the snow pack also indicates increased resistance, but was probably not caused by the application of pressure by the skis. This increase was probably caused by another external force, a ski track perhaps, earlier in the winter. Plot No. 3 - The plot was ski packed by four passes across it. Both plot 2 and 3 indicate approximately the same resistance in the top layer. It would appear that four trips across a snow mass gives no better results than one trip. Notice the small amount of resistance from the ground upwards to about the 50 cm. mark. The snow is very unstable and is composed of depth hoar. Plot No. 4 - This plot was boot packed thoroughly as is usually done on highly competitive ski race courses such as in the Olympics. After the boot packing, the surface was smoothed out by ski packing. As can be seen, this appears to be the most favorable method of producing the hardest ski surface which would resist the cutting action of the skis. This method produced the highest average resistance as offered to the penetrometer. This is also a method used on some slopes to prevent large climax avalanches from being set in motion during the winter. |