Click here to view the poster from the United States Geological Survey:
In the early evening of July 31, 1976 a large stationary thunderstorm released as much as 7.5 inches of rainfall in about an hour (about 12 inches in a few hours) in the upper reaches of the Big Thompson River drainage. This large amount of rainfall in such a short period of time produced a flash flood that caught residents and tourists by surprise. The immense volume of water that churned down the narrow Big Thompson Canyon scoured the river channel and destroyed everything in its path, including 418 homes, 52 businesses, numerous bridges, paved and unpaved roads, power and telephone lines, and many other structures. The tragedy claimed the lives of 144 people. Scores of other people narrowly escaped with their lives.
The Big Thompson flood ranks among the deadliest of Colorado’s recorded floods. It is one of several destructive floods in the United States that has shown the necessity of conducting research to determine the causes and effects of floods. The U.S. Geological Survey (USGS) conducts research and operates a Nationwide streamgage network to help understand and predict the magnitude and likelihood of large streamflow events such as the Big Thompson Flood. Such research and streamgage information are part of an ongoing USGS effort to reduce flood hazards and to increase public awareness.
After the September 2013 floods Allen Best wrote about being part of the disaster response in The Denver Post. It’s a good read. Here’s one passage:
I was at the Big Thompson disaster. I was living in Fort Collins then and was among scores of young men (sorry, women, those were different times) with strong backs who could be summoned in case of forest fires. My only fire was at an old sawmill site in the foothills. The joke was that one of us had set the fire because we were so desperate for minimum-wage work.
Then came July 31. It was hot that night in Fort Collins. It hadn’t rained a drop.
I was living above Gene’s Tavern, just two blocks from the Larimer County Courthouse. When the call came, I was at the sheriff’s office almost immediately. It was 9 p.m.
Being among the first at the command center at the Dam Store west of Loveland, near the mouth of Big Thompson Canyon, I was assigned to a pickup dispatched to look for people in the water near the turnoff to Masonville. Already, the river was out of its banks. From the darkness emerged a figure, dripping and confused. “I went fishing at Horsetooth (Reservoir) and was driving home and then there was all this water,” he sputtered. He was befuddled. So were we.
Our leader decided we’d best get out of there. From what I saw the next morning, that was an excellent decision. Water later covered the road there, too. I spent the night at the Dam Store as the water rose. Helicopters were dispatched, but there was little that could be done. Our lights revealed picnic baskets, beach balls and propane bottles bobbing in the dark, roiling water that raced past us, but never any hands summoning help.
In the morning, we found those hands. The bodies were stripped of clothing and covered with mud. The first I saw was of a woman who we guessed was 18, not much younger than I was then. This thin margin between life and death was startling in my young eyes.
Eventually, 144 people were declared victims of the flooding that night (although one turned up alive in 2008 in Oklahoma).
Estes Park got some rain, but not all that much. The larger story was partway down the canyon, in the Glen Haven and Glen Comfort areas, where the thunderstorm hovered. In just a few hours, it dropped 10 to 14 inches of water.
Downstream in the canyon, just above the Narrows, some people were unaware that anything was amiss until they went outside their houses and saw the water rising in their yards. It hadn’t even rained there. One cabin I saw a few days later was stripped of doors and windows but stood on its foundations, a mound of mud 5 or 6 feet high in the interior. I seem to recall a dog barking as we approached, protecting that small part of the familiar in a world gone mad.
At the old hydroelectric plant where my family had once enjoyed Sunday picnics, the brick building had vanished. Only the turbines and concrete foundation remained. In a nearby tree, amid the branches maybe 10 or 15 feet off the ground, hung a lifeless body.
The river that night carried 32,000 cubic feet per second of water at the mouth of the canyon, near where I was stationed. It happened almost instantaneously — and then it was gone. It was a flash flood.