About once a month, the other two techs head out to a grid of bamboo poles, carrying a box of brightly colored twine and a pair of scissors. Right down at the snow surface, they tie off one of the strings, and run it onward, girdling each set of four poles. Clip it off, and head to the next set of poles.
As snow accumulates on the surface, the strings are buried, and new strings laid atop. With time, this ever-deepening network of strings becomes a three-dimensional record of accumulation, and allows individual snow layers to be tracked over time. On rare occasion, the techs excavate alongside one of these accumulation grids, carefully strip back the snow, and examine the snow record and the long-buried strings.
It was one of these unusual excavation days, so I headed out to join Jason and Yuki and to put in some shovel time. We roughed out the access hole, and the techs headed back to the observatory to collect their sampling gear and don their contamination-reducing bunny suits. They looked like a pair of Finnish snipers in their camo-white outfits.
Down in the pit, with the strings still protected by a thick cap of snow, they performed a series of tests at regular depth intervals. They measured snowpack temperature, crystal size and character, snow hardness, and collected samples with a unique fixed-volume tool. Then, as archeologists, carefully uncovering the buried signs of science technicians past, we used a scraper to slowly enlarge our hole in the direction of the strings. The multicolored strings, when exposed, were a striking visual treat.
