Major Hurricanes Forming Earlier Due To Warming Oceans: Study

FLORIDA — A gradual increase in ocean temperatures is causing major, destructive hurricanes to form earlier now than they did decades ago, according to a new study.

The study, published this week in the journal "Nature" by a group of Chinese and U.S. researchers, defined “intense tropical cyclones” as a hurricane, typhoon or other tropical system with maximum sustained winds over 127 mph. According to the Saffir-Simpson scale, the study's definition would apply to any system at or above a strong Category 3 hurricane.

In the study, researchers found intense tropical cyclones were forming 3.7 days earlier per decade in the northern hemisphere and 3.2 days per decade earlier in the southern hemisphere. That's just over two weeks earlier in the northern hemisphere — or 15.5 days — since the study's analysis began in 1981.

Currently, the Atlantic hurricane season runs from June 1 to Nov. 30. According to NOAA, the first named storm typically forms in mid- to late June, the first hurricane tends to form in early to mid-August and the first major hurricane forms in late August or early September.

The 2023 hurricane season peaked on Sept. 10. Generally, intense tropical cyclones form more frequently in autumn because they require sufficient heat to form and develop.

However, according to the study's authors, the formation timeline is shifting shift due to warming ocean waters, accelerated by human-caused climate change.

The study's authors noted the shift in formation could pose devastating consequences to some areas as intense tropical cyclones could overlap more with extreme rainfall produced by summer weather systems — for example, the monsoon depression system.

The devastating impact of the compound hazards is well beyond any one of these events individually," the study's authors wrote. "They can induce substantial inland rain and flooding associated with multiple weather systems, causing large-scale failures of power and transportation systems, straining emergency responses and depleting disaster preparation resources."

Because of this, researchers stressed the need for additional research and adapted forecasting to protect those at high risk, according to the study.