The Big Thompson flood was one of the worst natural disasters in Colorado’s history. The Big Thompson River starts in Rocky Mountain National Park, winding its way eastward through the steep rock walled, 25 mile long canyon above Loveland. U.S. Highway 34 follows the river through the canyon.
There was an estimated 2,500 to 3,000 people in the canyon on Saturday evening July 31st, 1976. Light easterly winds aloft pushed very moist air up the eastern mountain slopes. At 6 pm thunderstorms began to develop over the Big Thompson drainage. Slow northerly storm movement, coupled with rapid development of new storm cells to the south, combined to produce a nearly stationary intense thunderstorm. This storm produced over 4 inches of rain from 6:30 pm to 11 pm over Big Thompson Canyon from near Estes Park to Drake. The most intense rainfall, up to 12 inches, occurred over the western third of the canyon.
In two hours, the Big Thompson Canyon flash flood killed 143 people, and many others suffered injuries. 418 houses and 52 business were destroyed with another 138 houses damaged. The flood caused more than $35 million in damages.
- Do not camp along streams and washes, particularly during threatening conditions. A flash flood can catch you while you're sleeping. Locate your camp on ground that is significantly higher than the stream or canyon.
- Stay tuned to what the weather is doing upstream. Rain upstream, perhaps many miles away, can roar down a canyon and catch you completely by surprise.
For additional information on the Big Thompson flood go to Colorado Remembers Big Thompson Canyon Flash Flood of 1976 at http://www.noaanews.noaa.gov/stories/s688.htm and Big Thompson Canyon/Big Thompson Flood at http://www.larimerco.com/5visitors/51004big_thompson.htm.