Oceans are supercharging hurricanes past Category 5
Deep ocean hot spots packed with heat are making the strongest hurricanes and typhoons more likely—and more dangerous. These regions, especially near the Philippines and the Caribbean, are expanding as climate change warms ocean waters far below the surface. As a result, storms powerful enough to exceed Category 5 are appearing more often, with over half occurring in just the past decade. Researchers say recognizing a new “Category 6” could improve public awareness and disaster planning.
Ocean regions that fuel the planet's most powerful hurricanes and typhoons are heating up in the North Atlantic and Western Pacific. These changes are being driven not just by warmer surface waters, but by heat that now extends far below the ocean surface. New research suggests that human-caused climate change may account for as much as 70% of the expansion of these storm-forming hot spots.
As these hot spots grow, they increase the likelihood that exceptionally intense tropical cyclones, sometimes described as Category '6' storms, could make landfall near heavily populated coastlines.
"The hot spot regions have expanded," said I-I Lin, a chair professor in the Department of Atmospheric Science at the National Taiwan University.
Lin shared the research during an oral presentation focused on tropical cyclones at AGU's 2025 Annual Meeting in New Orleans, Louisiana.
Why Scientists Are Calling for a New Storm Category
Lin has studied the most extreme hurricanes and typhoons for more than ten years. Her work intensified after Typhoon Haiyan -- also known as Super Typhoon Yolanda -- struck the Philippines at peak strength in November 2013, killing thousands of people. In 2014, Lin and her colleagues published research in the AGU journal Geophysical Research Letters arguing that storms of this magnitude warrant a new classification, Category 6.
Under their proposal, Category 6 tropical cyclones would include storms with wind speeds exceeding 160 knots. Until now, any storm stronger than 137 knots has been grouped into Category 5, which most weather agencies still consider the highest level. Lin noted that most hurricane categories span a range of about 20 knots, making a separate Category 6 more consistent with how storms are classified. Category 4, for example, includes winds between 114-137 knots.
The Strongest Storms on Record
Several well-known storms would fall into this proposed Category 6. Hurricane Wilma in 2005 remains the most intense hurricane ever measured in the Atlantic basin. Typhoon Haiyan also meets the criteria, as does Typhoon Hagibis, which hit Tokyo in 2019. Hagibis caused enormous damage from rain and wind, Lin said, even though the storm had weakened somewhat before reaching the city.
Another standout example is Hurricane Patricia, which developed in the Pacific Ocean off Mexico's coast. Patricia holds the record as the strongest tropical cyclone ever observed, with winds reaching up to 185 knots -- powerful enough to qualify as a Category 7 storm, if such a category existed, Lin said. "Patricia was the king of the world," she added.
Burgeoning ocean hotspots feed big storms
To understand how often these extreme storms occur, Lin and her team reviewed records of major tropical cyclones from roughly the past 40 years. Their analysis shows that storms exceeding 160 knots are appearing more frequently. Between 1982 and 2011, eight such storms were recorded. From 2013 to 2023, that number rose to 10.