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<br />
<br />IV
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<br />COI'TEI\TS
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<br />Page
<br />FIGURE 20. Geostationary Operational Environmental Satellite photograph, 1400 MDT, July 31. 1976......................... 25
<br />21. Map of Colorado and surrounding States showing regional surface analysis, 1600 MDT, July 31, 1976............... 26
<br />22. Map of Colorado and surrounding States showing radar summary for 1535 MDT, with locations of fronts and squall
<br />line for 1600 MDT. July 31, 1976.'.................................'''.....'..'''''''''''. 27
<br />23. Geostationary Operational Environmental Satellite photograph, 1600 MDT, July 31.1976......................... 28
<br />24. Plot of fawinsonde data obtained at Sterling, Colo.. 1602 MDT, July 31.1976,.,.............,.................... 29
<br />25. Map of Colorado and surrounding States showing regional surface analysis, 1800 MDT, July 31, 1976.....,......... 30
<br />26. Map of Colorado and surrounding States showing radar summary for 1735 MDT, with locations of fronts and squall
<br />line for 1800 MDT. July 31,1976""""",......."......"""""""",.,.,., __""""""""""", 31
<br />27. Geostationary Operational Environmental Satellite photograph, 1800 MDT, July 31,1976......................... 32
<br />28-31. Maps of western conterminous United States, southwestern Canada, and northern Mexico showing:
<br />28. Surface analysis, 1800 MDT, July 31,1976...........................,.......,.,...................... 33
<br />29. 700-millibar analysis, 1800 MDT, July 31, 1976.........................,.,...,...................... .. 34
<br />30, 500-millibar analysis, 1800 MDT, July 31, 1976,.........,....,..,....................""""""", __ 35
<br />31. Stability an.lysis, 1800 MDT, July 31. 1976.,..,..................... ....................,..",..... ., 36
<br />32. Plot ofrawinsonde data obtained at Denver, Colo., 1800MDT,July31,197 6........................,.........,... 37
<br />33-35. Graphs showing:
<br />33. Time series of surface winds, altimeter setting, and surface-air and dewpoint temperatures, Stapleton Inter-
<br />national Airport, Denver, Colo., 1600-2300 MDT, July 31, 1976....................... ................. 38
<br />34. Time series of winds, altimeter setting, and surface-air and dewpoint temperatures, Rocky Flats plant near
<br />Boulder, COlD" 1600-2300 MDT, July 31.1976 __"" __ """..", __."""""'" __ __ "" __..""..'" 39
<br />35. Time series of winds from the surface to a height of 2,000 feet, and surface-air and dewpoint temperatures,
<br />TableMountainnorthofBoulder,Colo.,I630-2030MDT,July31,l976..............................,.. 40
<br />36. Maps showing radar and surface analyses at about 30-minute intervals for the Denver-Fort Collins, Colo., area,
<br />1730-1900 MDT, July 31. 1976 __....., __.,..... __".... __"""""....,............,...."""""""", 41
<br />37. Interpolated plot ofrawinsonde data for Loveland, Colo.. 1800 MDT, July 31,1976..........................,..... 42
<br />38. Shaded-relief map of the Front Range in northeastern Colorado showing comparison of radar echoes observed at
<br />Limon and Grover, Colo................................................................................... 44
<br />39. Diagram of the physical model of the thunderstorms over the Big Thompson River at 1845 MDT, July 31, 1976..,... 45
<br />40. Photographs of a large thunderstorm several miles southwest of Lyons, Colo., at about 1830 MDT, July 31,1976.... 46
<br />41. Shaded-relief map showing total rainfall for July 31-August 2, 1976, along the Front Range in northeastern Colorado 47
<br />42. Graph showing cumulative rainfall at three stations in Boulder and Larimer Counties. Colo., July 3I-August 2. 1976. 49
<br />43. Maps showing radar echoes in the Denver-Fort Collins. Colo., area, observed at Limon, Colo.. from 1701 to 2200
<br />MDT, July 31, 1976", __"""""" __""""""""", ____ __. __, __ __""""""" __ __.............." 50
<br />44. Graph showing estimated cumulative rainfall at Glen Comfort and Glen Haven. Colo., July 31-August 1, 1976....... 57
<br />45. Map showing stream-gaging stations and miscellaneous measurement sites in flood area in Larimer and Weld Coun-
<br />ties.......................................................................................,.,.....,...., 58
<br />46. Discharge hydrograph for the Big Thompson River at Estes Park (Site 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
<br />47. Dischargehydrograph for Fish Creek near Estes Park (Site 2).. .................................................. 63
<br />48. Stage graph for the Big Thompson River near Estes Park (Site 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
<br />49, Photograph showing erosion along base of Olympus Dam caused by Dry Gulch floodwater. . . , . . . . . . . . . . . . . . . . . . . . . 64
<br />50. Discharge hydrograph for the North Fork Big Thompson River at Drake (Site 21~ unti12300 MDT on July 31.1976... 65
<br />51. Discharge hydrograph for rising stage at the Big Thompson River at mouth of canyon, near Drake (Site 23).......... 66
<br />52. Stage graph for Buckhorn Creek near Masonville (downstream site) , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
<br />53-56. Discharge hydrographs for:
<br />53. The Big Thompson River at mouth, near LaSalle (Site 28)....................................,.,.,.,...,... 68
<br />54. The Cache la Poudre River at mouth of canyon, near Fort Collins (Site 34) . . . , . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
<br />55. The Cache la Poudre River at Fort Collins (Site 36) . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . , . . . , . , . , . . . . . . . 69
<br />56. The Cache la Poudre River at mouth, near Greeley (Site 37) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . , . , . , . , . . . . . . . 70
<br />57-59. Photographs showing:
<br />57. Erosion damage to U.S. Highway 34 and to irrigation siphon at the gaging station on the Big Thompson River
<br />at mouth of canyon, near Drake (Site 23)...................................,.......................... 72
<br />58. Aerial views of Drake. . . . . . , . , . , . , . , . . . , . . . . . . . , . , . , . , . , . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
<br />59. Views of destroyed automobiles....,...........,.,...,.,..,.....,.......,.,.,.,.,....................... 74
<br />60. Diagram showing comparison between July 31-August 1. 1976, rainfalls and previously observed rainfalls in eastern
<br />Colorado ................................................................................................ 75
<br />61. Diagram showing relation of peak discharge to drainage area for flood of July 3I-August 1, 1976, and previous max-
<br />imum floods.. ,. ,...,. ,....,.,...............,.....,..... ,... ,...,.,...,........... ,.,.,................. 76
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