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<br />The floods of the Big Thompson and Cache la Poudre rivers were <br /> <br />history by 5 am August 1. Rainbucket surveys conducted by various federal <br /> <br />agencies indicated a peak point rainfall of 14 inches northwest of the <br /> <br />Glen Haven area. The peak rainfall area for the Big Thompson flood was <br /> <br />located in an area bounded by Storm Peak on the north, Glen Haven on the <br /> <br />east, Krueger Peak on the south, and Mummy Mountain on the west. The <br /> <br />Cache la Poudre flood was fed by peak rain fall bounded by Storm Peak on <br /> <br />the south, Chambers Lake on the west, Bald Mountain on the north, and <br /> <br />Rist Canyon on the south (see Diagram D). <br /> <br />Rainfall estimates continue to be made and accurate peak rainfall <br /> <br />rates may never be determined. Some local rainfall totals for the storm <br /> <br />included 7.40 inches in Rist Canyon; 1.10 inches in Bighorn Canyon (Sat. <br />only); CSU Foothills Campus, 1.40 inches; Poudre Park 3.4 inches, and <br /> <br />.33 - 1.5 inches in Fort Collins; Loveland .12 inches; and Horsetooth <br /> <br />Heights, 2.1 inches. Clearly a distinct east-to-west gradient in the <br /> <br />rainfall existed. This fact emphasizes the importance of the local terrain <br /> <br /> <br />in "locking" the thunderstorms into the foothills (see Diagram E). <br /> <br /> <br />Similarities between these weekend floods and the Rapid City Flood <br /> <br /> <br />of June 9, 1972 are striking. In both cases a stationary frontal system <br /> <br />helped to funnel tropical moisture into a mountainous area, a large, al- <br /> <br />most stationary thunderstorm system produced the flood waters, and wind <br /> <br />speeds were very high below mountain top levels and very light above moun- <br /> <br />tain level. Both floods affected areas of high tourist density and oc- <br /> <br />curred between 9 pm and midnight after earlier heavy mountain rains of <br /> <br />peak rainfall near 14 inches. Most of the rain fell in a 4 hour period <br /> <br />or less. <br /> <br />18 <br /> <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />