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Table 2.-Annual precipitation distribution 1974 1967 1960 1959 1972 1958 1971 1965 1954 1963 1948 1953 1961 1943 1947 1956 . 1936 1946 1952 1933 1934 1949 1932 1929 1945 1928 .1927 1944 1973 1924 1922 1942 1970 1919 1920 1940 1969 1968 1918 1914 1935 1941 1966 1938 1916 1913 1931 1939 1964 1930 1915 1904 1926 1937 1962 1925 1912 1902 1921 1910 1957 1917 1909 1901 1908 1906 1950 1955 1923 1911 1907 1900 1905 1899 1903 1951 0 25.4 50.8 76.2 10 1.6 127.0 152.4 177.8 203.1 228.6 254.0 cm (0) (10) (20) (30) (40) (50) (60) (70) (80) (90) (I 00) (in) Precipitation in centimeters (in) cm (in) cm (in) Mean 128,5 (50.6) Maximum 207.8 (81. 8) Median 123.7 (48.7) Minimum 48.0 (18.9) Variance 574.8 (226,3) Range 159.8 (62.9) Standard Coefficient of deviation 38.2 (15.0) variation 30,1 percent Annual precipitation totals can be very misleading in attempting to assess water totals available for storage in reservoirs and/ or water available for plant use. Heavy rains in the fall may constitute an abnormally large percentage of the total precipitation in a "normal" year. Excess water at this time of year must be released from reservoir storage to provide space required as a safety factor for expected winter and spring flow. Excess water in the soil from fall rains drains prior to spring/ summer plant moisture needs. Therefore, it is necessary to evaluate the timing of precipitation, Distribution in Time.-Knowledge of when precipitation accumulation occurs is vital to the timing of cloud seeding operations. Figure 4 illustrates the enormous variability in precipitation timing, In an average year, 25 percent of the total precipitation occurs by December 18. In 1899, however, it fell as early as October 23. In 1917, the 25-percent level was not recorded until 1-6