A chinook wind can be catastrophic for a snow cover. Assume that the ground is covered by a 40-cm depth of snow with a density of 0.1 gram per cubic cm at a uniform temperature of 0 °C. How much heat energy in calories per square cm is required to melt all the snow? (Consider the column volume as 1 sq. cm by 40 cm depth. The latent heat of melting is 80 calories per gram.) Answer: __________ calories per square cm.