1976 – July 31, Supercell Storm, Flash Flood, Big Thompson Canyon, CO — 144
— 145 Smith, Roger. Catastrophes and Disasters. Edinburgh & NY: Chambers, 1992, p.119.[1]
— 144 Burt and Stroud. Extreme Weather: A Guide & Record Book. 2004, 132.
— 144 Drabek, Thomas E. The Human Side of Disaster. Boca Raton, FL: CRC Press, 2010, 49.
— 144 Nelson. Colorado Weather Almanac, 2007, p. 219.
— 144 Paulson, et al. “National Water Summary 1988-89 – Hydrologic Events and Floods…”
— 144 Perry/USGS. Significant Floods in the United States During the 20th Century. 2000
— 144 USGS. Summary of Significant Floods in the US, PR, and the VI, 1970-1989. 2008.
— 144 Webley and Holmes (USGS). “Top 10 Historic U.S. Floods.” Time. 5-11-2011.
— 139 Ludlum. The American Weather Book. 1982, pp. 82 & 85.
–<135 NWS. Historic Flood Events in the Missouri River Basin, “Flash Floods,” 2008
Narrative Information
Burt and Stroud: “Colorado’s Big Thompson Canyon flood was the result of a stationary thunderstorm dropping phenomenal amounts of rain over a watershed of many narrow stream valleys… an estimated 14” of rain fell in a four-hour period near Estes Park at the headwaters of the Big Thompson River. A dam collapsed and a wall of water perhaps 20-feet deep roared down the canyon, sweeping all before it. In places where the creek would normally be only 18” deep it became 34 feet deep as measured by the debris stream. Tragically, the event occurred on a Saturday afternoon in summer when many tourists and locals were camping along the river valley or staying in motels in the canyon. Deaths numbered 144 and many bodies were never recovered.” (Burt and Stroud. Extreme Weather: A Guide & Record Book. 2004, 132.)
Ludlum: “Severe flooding began shortly after 7:00 p.m., with the crest reaching and destroying the small town of Drake at the river’s junction with its North Fork about 9:00 p.m…. A wall of water estimated to be 19 ft…high swept tremendous amounts of debris downstream, including large trees and numerous structures. A survey reported 323 houses and 96 mobile homes destroyed. The Loveland municipal power plant, a brick building, was lifted from its foundations, and much additional damage resulted in the towns on the plains beyond the canyon mouth. Total losses were estimated at $30 million.
“The storm took at least 139 lives in its sweep of the canyon. Several more were reported missing long after the flood. Most campers had no warning of the wall of water about to descend on them.” (Ludlum. The American Weather Book. 1982, 85.
NWS: “On the evening of July 31, 1976, in less than a 6-hour period, very heavy rain fell over a 70 square-mile area. More than 12 inches fell over the slopes of the western third of the Big Thompson Canyon and more than four inches of rain fell over the entire canyon area from near Estes Park to Drake, Colorado. The resulting flooding was devastating; over 135 persons were killed.” (NWS, Historic Flood Events in the Missouri River Basin, Missouri Basin/Pleasant Hill River Forecast Center, 2008.)
Paulson: “The flood of July 31-August 1, 1976, on the Big Thompson and Cache la Poudre Rivers, resulted in at least 144 deaths and total damage of about $39 million (McCain and others, 1979, p. 70, 71).[2] Some of the peak discharges on the Big Thompson River were extremely rare; the largest was about four times that having a 100-year recurrence interval. Other peak discharges, especially on the Cache la Poudre River, were not as significant. This flood was produced by 6- 12 inches of rainfall from a storm centered over the downstream part of the Big Thompson River basin during the evening of July 31, 1976. Many of the lives lost were campers who had set their camps near the river.” (Paulson, et al, 1989.)
USGS: “The second largest flood disaster of 1976 was the Big Thompson River flood in Colorado. The area most affected by the flood was the Big Thompson Canyon, especially the area downstream from Estes Park, Colorado. The flood was caused by a storm on July 31 through August 1, with rainfall amounts totaling as much as 12 in. in some areas (National Oceanic and Atmospheric Administration, 1976); an estimated 7.5 in. of rain fell in some areas in 1 hour. Maximum discharges on the North Fork Big Thompson and Big Thompson Rivers exceeded previously recorded maximums at several locations. Reports of an estimated 19-ft high wall of water rushed through Big Thompson Canyon destroying everything in its path. In the narrows of the canyon, stream levels rose to 14 ft above pre-flood levels and washed away 1.9 mi of highway. The flood resulted in 139 deaths and 5 missing persons, destroyed 323 homes and 96 mobile homes, and damaged many other homes. Two counties were declared Federal disaster areas, and the flood caused $39 million in damages (Paulson and others, 1991[3]).”
(USGS. Summary of Significant Floods in the US, PR, and the VI, 1970-1989. 2008.)
Sources
Burt, Christopher C. and Mark Stroud. Extreme Weather: A Guide & Record Book. W. W. Norton & Co., 2004, 304 pages. Google preview accessed 1-1-2014 at: http://books.google.com/books?id=NuP7ATq9nWgC&printsec=frontcover#v=onepage&q&f=false
Drabek, Thomas E. The Human Side of Disaster. Boca Raton, FL: CRC Press, 2010.
Ludlum, David M. The American Weather Book. Boston: Houghton Mifflin Co., 1982.
National Weather Service Weather Forecast Center, Pleasant Hill, MO. Historic Flood Events in the Missouri River Basin. NWS/NOAA, 7-29-2008. At: http://www.crh.noaa.gov/mbrfc/?n=flood
Nelson, Mike. Colorado Weather Almanac. Big Earth Pubs., 2007. Partially Google digitized. Accessed 8-21-2017 at: http://books.google.com/books?id=05yxTU60z2kC&printsec=frontcover&source=gbs_v2_summary_r&cad=0#v=onepage&q=&f=false
Paulson, R.W., E.B. Chase, R.S. Roberts, and D.W. Moody (Compilers). “National Water Summary 1988-89 – Hydrologic Events and Floods and Droughts. U.S. Geological Survey Water-Supply Paper 2375; excerpted in Major Floods and Droughts in California (website). 1991. Accessed 10-9-2009 at: http://geochange.er.usgs.gov/sw/impacts/hydrology/state_fd/cawater1.html
Perry, Charles A. Significant Floods in the United States During the 20th Century – USGS Measures a Century of Floods (USGS Fact Sheet 024-00). USGS Kansas Water Science Center, March 2000, Accessed 8-21-2017 at: http://ks.water.usgs.gov/pubs/fact-sheets/fs.024-00.html
Smith, Roger. Catastrophes and Disasters. Edinburgh and New York: W & R Chambers, 1992.
United States Geological Survey. Summary of Significant Floods in the United States, Puerto Rico, and the Virgin Islands, 1970 Through 1989 (Water-Supply Paper 2502). USGS Kansas Water Science Center, Sep 17, 2008. Accessed 11-12-2016 at: http://ks.water.usgs.gov/pubs/reports/wsp.2502.contents.html#HDR1
Webley, Kayla and Robert Holmes (USGS). “Top 10 Historic U.S. Floods.” Time. 5-11-2011. Accessed 8-21-2017 at: http://www.time.com/time/specials/packages/article/0,28804,2070796_2070798,00.html?xid=rss-specials
[1] In that the USGS and most of the other sources cited note 144 deaths, and Smith provides no source citation, we choose to show the figure of 144 fatalities.
[2] McCain, J.F., Hoxit, L.R., Maddox, R.A., and others, 1979, Storm and flood of July 31-August 1, 1976, in the Big Thompson River and Cache la Poudre River basins, Larimer and Weld Counties, Colorado: U.S. Geological Survey Professional Paper 1115, 152 p.
[3] Paulson, R.W., Chase, E.B., Roberts, R.S., and Moody, D.W., compilers, 1991, National water summary, 1988-89-Hydrologic events and floods and droughts: U.S. Geological Survey Water-Supply Paper 2375, 591 p.