Tropical Storm Imelda enters the history books as one of the top five wettest tropical cyclones to ever strike the lower 48 states, with a maximum rainfall total of 43.39 inches. On Friday morning, floodwaters continued to block roads, damage homes and cause gridlock in the Houston metro area and especially in the vicinity of Beaumont and Port Arthur, where new flood warnings were issued for additional rainfall of up to four inches.
That this storm comes just two years after Hurricane Harvey dumped an almost unimaginable 60.58 inches of rain on the same general area is no accident. In addition, other major rain events in Southeast Texas in the past five years have caused extensive disruptions and damage.
Recent studies show that slow-moving tropical cyclones in the United States are becoming more frequent, and increased ocean heat content is supercharging the rainfall potential of such storms, making them more formidable rain producers than they otherwise would be.
For example, a study published in the journal Earth’s Future in 2018 found that Hurricane Harvey’s gargantuan rainfall totals were directly related to record high ocean heat content in the western Gulf of Mexico. The oceans are absorbing the vast majority of extra heat from human-caused greenhouse gas emissions, with temperatures increasing in the process.