Thermal conductivity of snow by a transient state probe method

A transient state thermal conductivity probe (¼″ in diameter, 30″ in length) is described along with the method by which it is used to measure thermal conductivity of snow. Heat is supplied electrically at a constant rate to the probe at a given time after insertion into the sample. After a four minute lag, a plot of probe temperature rise against logarithm of time since the start of heating, gives a straight line whose slope is inversely proportional to sample thermal conductivity and proportional to the heating rate. The probe was calibrated against a standardized oil, and the constant was found to be unity. Values for artificially packed snow in the laboratory agreed with published data. However, values found in the field were considerably lower. The device is recommended for field measurements since data can be obtained with minimum disturbance of the snow.