National Weather Service United States Department of Commerce

Extreme Heat in the Central US Expands to the Southeast; Severe Weather & Flash Flooding Threats in the Plains & Upper Midwest Tonight.

Dangerous heat continues across portions of the Central and Southeast U.S. through July. Heavy rains, flooding, & severe weather are possible across the Plains & Upper Midwest to the upper Great Lakes tonight, with the heavy rain and flooding threat continuing through Friday. Tropical Depression 12W brings heavy rain to Guam & the Marianas through Saturday. Read More >

Flood Return Period Calculator

Though this calculator is worded for the flood event return period it would work for any extreme weather event.

 

Enter the return period (ie..100 year flood)

Percent chance of occurrence

year flood %
Enter the number of years (ie..over the next 10 years)
There is a % chance that a year flood will occur over the next year(s)
year(s)