National Weather Service United States Department of Commerce

Atmospheric River Impacting California

A major winter storm with an active atmospheric river is inundating California the next few days with a tremendous amount of moisture. Heavy to excessive rainfall is likely from central to southern California that may produce flooding along with mudslides and dangerous debris flows near recent and vulnerable burn scars. A significant amount of snow is anticipated in the Sierra with feet of snow. 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)