APPLICATION OF CAPACITANCE INSTRUMENTATION TO THE MEASUREMENT OF DENSITY AND VELOCITY OF FLOWING SNOW

We describe capacitance instrumentation suitable for the measurement o f density and velocity of flowing snow with moderate liquid-phase wate r content. A wand, consisting of two adjacent sensors protected by gua rd circuits, produces signals that are related to snow density through calibration. Cross-correlation of the signals permits velocity measur ements. Calibration is accomplished using a capacitance device that re cords the dielectric properties of a snow sample while subjecting it t o controlled levels of compaction and volume change. Non-invasive prob e geometries are also presented. The instrumentation is tested in arti ficial and natural avalanches.