Nevada cooperative snow‐surveys—Eastern slope, central Sierra Nevada: Comparison of forecast and actual results, 1939

In the above comparison the forecast‐figures were for probable runoff of rivers and rise of Lake Tahoe. The possible minimum estimate which is always given on the regular actual forecast‐reports is based on assuming a considerable deficiency in spring and summer precipitation. Actually in 1939 the April–May precipitation at Tahoe City was only about 54 per cent of normal and April–June and April–July only 49 per cent of normal. The deficiency, especially in the April–May period, most of which was in April, helps to account for the deficiency in the runoff of the Truckee River. Had this spring precipitation been normal, the rise of Tahoe and runoff of the Walker and Carson rivers would have been noticeably above the forecast.