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. 19. RAINFALL a. Durillg the afternoon of 16 June. unprecedented8lllounts of rain (estimated up to 14 inches in a few hours at Larkspur, Colorado and 10 inches near Castle Rock. Colorado) fell .on the drainage areas of East .and West Plum Creeks in the foothills of the Palmer Lake area. The average 6-hourrainfall over 1,000 square miles was 4.8 inches. Again, on the 17th of June, heavy rains occurred across eastern Colorado. A series of 12- to l4-inch centers were reported in the Falcon, Peyton, and Fords, Colorado area northeast of Colorado Springs. The average 6-hour rainfall over 1,000 square miles was 7.8 inches. Other centers with total rainfall values of 18 inches or more during this. period were reported near Two Buttes, and Holly, Colorado. b. Unsettled weather continued until 26 July 1965. with repeated rainfall and runoff in areas of earlier flooding. During the period 23 to 26 July, the stom pattern also extended over the foothills areas of the Bear Cr.eek and Clear Creek watersheds. 20. PATTERNS OF FLOODING a. On the 14th and 15th of June, flood stages on tributary stre8llls in the northern portions of the South Platte River basin closed roads and. damaged private property in low-lying areas. The principalstre8llls in flood stage in the lower South Platte River basin were Lone Tree Creek, Crow Creek, Pawnee Creek in Colorado, and Lodgepole Creek in Nebraska. Tornado damage and runoff from smaller contributory drainage areas made it difficult to determine the sources and causes of d8lllages in some areas.. b. On the afternoon of the 16th of June, storm runoff caused unprecedented discharges and extensive damages along East and West Plum Creeks which combined to cause record flood stages on lower Plum Creek. The flood entered the South Platte River south of Denver at approximately 7 p.m. on the 16th. It destroyed or damaged every- thing in its path through the 44-mile reach of metropolitan Denver before spreading out into the agricultural flood plain north and east of Denver. While the Plum Creek flood passed through Denver, heavy runoff from the upper Cherry Creek watershed caused considerable d8lllege above Cherry Creek Reservoir, but additional d8lllage to Denver was prevented when the reservoir impounded the entire flood volume. Because the storm pattern extended over the Sand and TollGate Creek watersheds, heavy runoff from these stre8lllsdestroyed bridges and track facilities in the vicinity of Aurora, Colorado, and contributed additional flood volume to the South Platte River Just north of Denver prOper. As the flood passed downstre8lll, heavy runoff from the Cache LsPoudre River and the Big Thompson River contributed their volume to upstre8lll discharges attenuated bw valley storage. . 11