September 2013 brought catastrophic flooding to Colorado, taking lives and changing landscapes in what will almost certainly become one of the state’s costliest disasters in history. Many communities along the Front Range experienced 100 year and even 1000 year flooding, which means that in any given year there is only a 1% or 0.1% chance for such an event to occur respectively.
September 2013 was Colorado's wettest month on record, an incredible 2.7" above average statewide. Most of the precipitation that fell occurred over an eight day stretch from September 9, 2013 to September 16, 2013 across northeast Colorado and the Front Range.
In a region accustomed to 300 days of sunshine each year, the semi-arid climate of Colorado's Front Range rarely sees consecutive days of rain in a given year. The monsoonal flow that feeds Colorado’s short-lived but powerful summer thunderstorms normally comes to an end in late August. In 2013, the monsoons continued well into the month of September.
During Colorado’s eight days of rain the canyons near Boulder turned into deadly traps, the town of Lyons became severed from the rest of the state, and unprecedented amounts of water surged toward the eastern plains.