Heavy Rainfall Frequencies for the U.S.

Rainfall Frequencies by State

These data are useful in, and often required for, the engineering design of any structure subject to the affects of heavy rainfall-such as drainage culverts, pipes, roof tops, etc. The new publications, which are linked here, provide users with rainfall frequency distributions which are more detailed than (and often differ from) the previous publications. The NWS Hydrometeorological Design Studies Center has issued a web page ("Current Precipitation Frequency Information and Publications") which lists which publications should be used for each state, and the time periods for which each should be used (5 min-60 min, 1 hr-24 hr, and 2-day-10-day periods).

NOAA Atlas 14

• Semiarid Southwest
  NOAA - Atlas 2 is no longer valid for the "Semiarid Southwest." This includes the following states: Arizona, Nevada, New Mexico, Utah, and Southeast California. For these states, NOAA - Atlas 2 (Volumes 4, 6, 7, 8 and part of 11) has been replaced by NOAA Atlas 14, Volume 1. This publication is available ONLY as an online version and can also be found at: http://www.nws.noaa.gov/oh/hdsc/currentpf.htm
  
  
• Ohio River Valley
  Hydro-35 and Tech Paper No. 40 are no longer valid for most states in the Ohio River Valley and surrounding states. This includes the following states: Delaware, Illinois, Indiana, Kentucky, Maryland, New Jersey, North Carolina, Ohio, Pennsylvania, South Carolina, Tennessee, Virginia, West Virginia, and Washington, DC. For these states, Hydro-35 and Tech Paper -40 have been replaced by NOAA Atlas 14, Volume 2. This publication is available ONLY as an online version and can be found at: http://www.nws.noaa.gov/oh/hdsc/currentpf.htm