Rapid attribution of the August 2016 flood-inducing extreme precipitation in south Louisiana to climate change

Note: The findings presented in this study were originally done as part of a rapid attribution analysis in September 2016, available here

• Finds that the probability of a 3-day precipitation extreme like the event observed August 12th-14th occurring anywhere in the Central Gulf Coast region has increased and the increase is due to human-caused climate change
• Finds that an event like this is now expected to occur at least 40 percent more often than it was in our pre-industrial past
• Finds that the increase in probability corresponds to an increase in intensity of roughly 10%
• Finds that the probability for a comparable three-day extreme precipitation event at a single station as high as what was observed August 12-14 (25.5 inches) is somewhere between a 1-in-450 year and a 1-in-1450 year event (note: it was not the maximum rainfall at a single station that resulted in such catastrophic flooding, it was the total rainfall over the entire affected area)
• States that the event is best characterized as a 1-in-550 year event locally
• States that an event like this currently occurs somewhere along the Central U.S. Gulf Coast region about once every 30 years (between 11 and 110 years)