Hurricane Harvey

Hurricane Harvey is tied with Hurricane Katrina as the costliest tropical cyclone on record, inflicting $125 billion (2017 USD) in damage, primarily from catastrophic rainfall-triggered flooding in the Houston metropolitan area. It was the first major hurricane to make landfall in the United States since Wilma in 2005, ending a record 12-year span in which no hurricanes made landfall at such an intensity in the country. In a four-day period, many areas received more than 40 inches (1,000 mm) of rain as the system slowly meandered over eastern Texas and adjacent waters, causing unprecedented flooding. With peak accumulations of 60.58 in (1,539 mm), Harvey was the wettest tropical cyclone on record in the United States. The resulting floods inundated hundreds of thousands of homes, displaced more than 30,000 people, and prompted more than 17,000 rescues.

Harvey approached Houston over sea-surface waters which were significantly above average temperatures. Warm waters provide the main source of energy for hurricanes, and increased ocean heat can result in storms being larger, more intense and longer lasting, in particular bringing greatly increased rainfall. Sea level rise added to the resulting problems. According to officials from the Harris County Flood Control District, Harvey caused the third '500-year' flood in three years. The National Climate Assessment states:

"The recent increases in activity are linked, in part, to higher sea surface temperatures in the region that Atlantic hurricanes form in and move through. Numerous factors have been shown to influence these local sea surface temperatures, including natural variability, human-induced emissions of heat-trapping gases, and particulate pollution. Quantifying the relative contributions of natural and human-caused factors is an active focus of research."

From Hurricane Harvey in Wikipedia