|January's field practice was oriented around oversnow evacuation. It involved an oversnow approach, a five hundred lineal foot raising (on a 38 degree slope), a three hundred foot horizontal traverse across the slope, and a lowering through two stations before a final quarter mile evacuation to the truck. We met at Hoodoo Ski Area and proceeded uphill to the base of Hayrick Butte. A snow pit revealed the top 18 inches of the snowpack had a couple of layers with reasonably good cohesion and very good adhesion to the consolidated snow below. We stayed close to a band of exposed rocks for the ascent.
|A standard lowering system with main and belay lines and separate anchor systems was rigged just above the litter, and a second station about 250 feet down slope. Throughout the exercise, only snow anchors (pickets and flukes) were used. Boot packing the area into which the anchors were placed and letting the snow "age" made the placements much more solid. Using pickets greatly facilitated relocating the anchors.
Two 300 foot lines were bent together and a simple pulley system (3:1) was rigged using the raising line. The litter was raised to the top of the slope. From this station, a 300 foot tensioned line was rigged across the slope while the litter was fitted with a side-bridle consisting of pulleys at the head and foot of the litter. The pulleys were attached to the tensioned line (think of it as a "low-line" trackline) and the litter was drawn across the slope. Once it arrived at the second station, the litter was put on a platform while the lowering section was rigged.
The weather cooperated with temperatures in the mid-20's, snow showers at times and clearing at other times. The ropes got a good "dry cleaning" by dragging them through the snow. Some of us learned its easier to drag a loaded litter on snowshoes than on skis. No matter what you had on your feet, having (ski) poles made balance (and pulling) much easier.
Participants: L. Clunes, J. Dagata, B. Freund, S. Linn, K. Vertanen, and guest: Kathy Blackburn