The three highest-volume U.S. rainfall events on record happened in the past three years

Dr. Jeff Masters
8 December 2018
(Weather Underground) – Preliminary research by precipitation expert Dr. Kenneth Kunkel of the North Carolina Institute for Climate Studies, announced in September 2018, found that the three highest-volume rainfall events in the U.S. in the last 70 years have occurred since 2016: Hurricane Harvey in Texas/Louisiana in 2017, Hurricane Florence in North Carolina in 2018, and a March 2016 storm in Louisiana. It is highly unusual to get three such extreme events in one three-year period, and the odds of this occurring were increased by global warming, which boosts the amount of water vapor in the air and increases the frequency and intensity of heavy precipitation events.Dr. Kunkel’s ratings were based on four-day rainfall totals over an area of 14,000 square miles (an area 40% larger than the state of Maryland). Harvey delivered an average of 25.6 inches of rain over an area of 14,000 square miles, while Florence was a somewhat distant second place, with an average of 17.5 inches of rain over a like-sized area.The analysis only used stations that have been reporting reliably throughout the 70-year period, so only a small fraction of current reporting stations were used. However, the use of a consistent network of stations across the entire period increases the reliability of the resulting rankings. When looking at a bigger area–20,000 square mile–Harvey remained in first place, 1998′s Hurricane Georges was second, and Hurricane Florence fell to seventh place. The analysis has not been published or peer reviewed yet, but will be presented at the January 2019 meeting of the American Meteorological Society, Kunkel said. Below is a short description of the top-ten list of highest-volume U.S. rainfall events over a 14,000 square mile area over the past 70 years. [more]

The 3 Highest-Volume U.S. Rainfall Events on Record Have Happened in the Past 3 Years