On September 9, 2013, rain began to fall in eastern Colorado as a large low-pressure system pulled plumes of tropical moisture northward from the Pacific Ocean and the Gulf of Mexico. By September 16, 2013, as much as 12 to 20 inches of rain had fallen
Kimbrough, Robert A. rakimbro@usgs.gov,Holmes, Jr., Robert R. bholmes@usgs.gov. Flooding in the South Platte River and Fountain Creek Basins in eastern Colorado, September 9???18, 2013. 2015-01-01.