A knowledge of the permittivity and loss tangent of snow and ice is essential in studying both radar echoes from snow‐covered terrain and the attenuation of microwave energy through snowstorms. To provide this information, a program was carried out at the National Research Council of Canada to measure the permittivity and loss tangent of ice and snow, and also to determine the reflection coefficients of snow‐covered surfaces, at a wavelength of 3.2 centimeters.As a result of these investigations values have been obtained for the permittivity and loss tangent of snow of varying density, temperature, and water content. Theoretical values of the reflection coefficients of snow‐covered surfaces, calculated from these data, are compared with the values obtained from the direct measurement of reflections from natural snow surfaces.