Here come the good skiiers. The instrument you see on the right is a sonic distance sensor. It is designed to measure the distance to a snow surface by measuring the length of time it takes for a sound to go from the sensor, bounce off the snow and return to the sensor. So when it makes its measurement it goes "click, click, click." This area of the Alps is a high-accumulation, high-melt area so by the end of the summer this instrument will be almost three meters above the snow/ice surface.