Big Thompson Canyon is one of the most scenic areas of Colorado. An hour west of Denver, US-34 runs right along the Big Thompson River through much of the 25 mile long canyon.
The weekend of July 31-August 1, 1976 was the Centennial Celebration of Colorado Statehood. Thousands of hikers and campers crowded into the Canyon that weekend to enjoy a busy summer weekend of recreation.
On that fateful Saturday afternoon the 31st, easterly surface winds were blowing warm, humid air up the Front Range of the Rockies. As the unstable air rose, it condensed into a huge thunderstorm over Estes Park. Winds aloft were very light and the storm remained stationary over the same area for hours.
Beginning at 8:30 p.m., as much as twelve inches or rain was dumped directly on the canyon by the thunderstorm. Eight inches fell in just two hours at Glen Haven and Glen Comfort. The rock walls of the steep canyon did not soak up any of the rainfall and the river quickly rose. A twenty foot wall of water poured down the canyon, taking everything in its path, including unwitting campers and residents.
A total of 139 people were killed in the flood and the bodies of six people were never found. Before the flood event, the streamflow on the river was a meager 127 cubic feet per second. At the peak of the flood, it was an unthinkable 31,200 cubic feet per second.
It took over a year to rebuild Highway 34. Damage totaled over $35 million. Visitors to Front Range canyons now find signs warning them to climb to safety in case of flash floods.
