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<br />3 <br /> <br />According to the National Oceanic ,~ Atmospheric Administration <br /> <br />(NOAA) report on the Big Thompson flood (1976), heavy ratn fell over a <br /> <br />70 square mile area in the central portion of the Big Thompson watershed <br />between 6:30 and 11 :00 PM on July 31, 19'76. The most intense rainfall, <br />over 12 inches, fell over slopes in the western end of the canyon. <br />Figure 2 shows the distribution of rain that night in the canyon. <br />The impact of the flood could have been worse. The North Fork peak <br />streamflow occurred approximately 40 minlJtes later than the Main Fork <br />peak. If the two peaks had coincided, the peak str'eamflow would have <br />been much greater than the 31,200 cubic feet per second (cfs) officially <br />recorded at the mouth of the canyon (U.S. Geologica,l Survey,1976: 5). <br />One hundred thirty-nine people died in the flood, eighty..eight <br /> <br />people were injured, and six people are still missing.* According <br /> <br />to the Geological Society of A1T,erica report (1976:: 4), the flood destroyed <br /> <br /> <br />316 homes, 45 mobile homes and 52 busi nesses, and i'3 homes suffered <br /> <br />major damage. <br /> <br />THE WARNING EXPERIENCE <br /> <br />The NOAA report following the flood (1976) discusses the warning <br />process and the difficulties met wit.h by Denver staff meteorologists trying <br />to determine the situation in the vicinity of the Big Thompson Canyon <br />prior to the flood. The meteorologists had little luck in locating in- <br />formation on the situation. According to several of the deput'ies and <br />highway patrolmen who issued warnings, most of the people in the Big <br />Thompson Canyon July 31, 1976 were not warned officially. The person- <br />to-person warning concentrated on the area at the mouth of the canyon. <br /> <br />*Some officials estimate that theroe are still 25-40 bodies <br />buried in the debris which will never be found. <br />