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In the early evening of July 31, 1976, the day prior to Colorado’s centennial, a year’s worth of rain fell in 70 minutes over the headwaters of the Big Thompson River. The subsequent flooding of Big Thompson Canyon marked one of the deadliest natural disasters in the state, taking 144 lives and costing millions of dollars in damage. 

Links to information about this event, and the 2013 flash floods that occurred in the same area can be found here: 

1976 Big Thompson flood, Colorado | U.S. Geological Survey ( 

Big Thompson Floods of 1976 and 2013 - A Visual Comparison | U.S. Geological Survey ( 


Access real-time water information about Colorado via the National Water Dashboard


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