“Copious amounts of tropical moisture flowed northward from the Pacific Ocean and Gulf of Mexico into eastern Colorado on September 9–16, 2013. The combination of a slow moving upper-level system over the Great Basin region, favorable upslope easterly flow along the Front Range, and the presence of a stalled frontal system resulted in several episodes of torrential rainfall. The heaviest rain fell on the evenings of September 11–12. By week’s end, a swath of 8–17 inches of rain resulted in widespread, devastating flash flooding in the South Platte River Basin from Denver downstream to western Nebraska and in the upper Arkansas River Basin along the upper Fountain Creek. There were eight fatalities directly attributed to the flooding.
Because of the significant impacts of the event, the National Oceanic and Atmospheric Administration’s National Weather Service formed a service assessment team to evaluate its performance before and during the record flooding. The findings and recommendations from this assessment will be factored into the 2015 Annual Operating Plan to improve the quality of operational National Weather Service products and services and enhance its ability to provide an increase in public education and awareness materials relating to flash flooding, areal flooding, and river flooding. The ultimate goal of this report is to help the National Weather Service meet its mission of protecting lives and property and enhancing the national economy.”