A portable capacitance snow sounding instrument

We describe a penetration field-portable capacitance instrument capable of recording profiles of dielectric permittivity through a relatively dry snow pack. It consists of a wedged capacitance tip mounted at the end of a penetration pole. By appropriate placement of its reference, guard and sensor conductive surfaces, the capacitor sheds horizontal electric field lines resolving horizontal snow layers of 2.5-mm thickness. A prototype of the probe was tested at the mountain resort of Alta near Salt Lake City, Utah. There, it recorded the real and imaginary parts of the dielectric constant through a typical winter snow pack. Using independent calibrations, measurements of the dielectric modulus provided an accurate profile of density later confirmed by the excavation of a detailed snow cover profile.