Use of snow surveys in planning regulation of Columbia River floods

A practical method for making predictions of volumetric yield and flood discharges from snow is presented. Available data on the water stored in snow in the spring and during subsequent precipitation are obtained from 43 selected snow courses. The predictions are accompanied by estimates of error and probable limits within which the real yield or flood discharge is likely to fall, by statistical means. Two-thirds of the total error in predicting peak discharges is in the error associated with the relations of flood volume to snow water. Later season forecasts become progressively more precise. The effects of early season temperatures on peak discharge were indirectly evaluated by subtracting April volume from the estimated April-June volume, and relating flood discharges only to the remaining amount expected to flow during the last part of the 3-month period.Discussion by Clarence Pederson.