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basin. Magnitudes start at the 3 month time scale at 0.5 (0.6) for the Yampa-White (YW) up to 0.9 (1.0) for the Lower Arkansas (LAR) with the dry magnitudes slightly less than the wet magnitudes in parentheses. As the time scale increases for 3 months to 24 months nearly all of the magnitudes have increased to greater than 1.0 which is the average annual precipitation. From 24 months to 48 months time scale only small changes occur and in some basins the values actually decrease. The conclusion is that the worst droughts or wet periods in Colorado are usually associated with precipitation deficits or surpluses that equal or exceed the annual average precipitation locally. Examination of Table 10 shows that the actual ranges are quite larger at individual locations. Examination of Table 10 also reveals that the dates of the worst dry and wet periods have a wide range and do not group easily into the broad time periods identified in Table 4. This is simply the reality of how variable precipitation is especially where convective rainfall in the summer is important. A companion to Table 10 for duration of dry and wet events is given in Table 11. This shows that these major dry or wet events last longer than one year and the duration increases with increasing time scale. Examples of the extent and severity of drought and wet events are shown on the maps of Figure 12a-d. Two of the worst droughts this century were present in March 1935 (Figure 12a) and September 1956 (Figure 12b). Both show more than 40% of the state in drought. Note the' maps do not have areas blocked off but most higher elevations are not represented by observations. There has not been such a widespread drought in Colorado at the 12 month time scale since the 1950s. There is no known reason why droughts ofthis nature should not return again. Two exceptionally wet periods are shown in October 1957 (Figure 12c) and June 1995 (Figure 12d) for the 12 month time scale. These also have more than 40% of the state in wet conditions. Each of these dry or wet periods are more extreme in a sub-portion of the state. The 22