Tropical Storms Capable of Driving Catastrophic Hurricanes That Spread Across the Ocean
Milton. Haiyan. Patricia. These names bring to mind the tropical storms with the highest number that have fueled the debate over whether we need “Category 6” hurricanes. One team of experts believes us, especially because their latest research suggests that these storms are an increasing threat to populated areas.
II Lin, chair professor in the Department of Atmospheric Sciences at National Taiwan University, presented his team’s research at the annual meeting of the American Geophysical Union (AGU) in New Orleans on Wednesday. The findings, which are yet to be peer-reviewed, show that regional “hot spots” of above-average ocean temperatures in the North Atlantic and western Pacific—incubators of superstorms—are growing rapidly.
Lin and his colleagues believe this strengthens the case for Category 6, which can help cities better prepare for the impact of more powerful storms—especially in areas where they are more common.
“We really think there is a need to provide the public with very important information,” Lin said in the AGU release.
Section 6 case
Typhoon Haiyan struck the Philippines in 2013, killing at least 6,300 people and displacing millions more. A year later, Lin led a study that attributed Haiyan’s unprecedented intensity in large part to warm groundwater temperatures in the tropical western Pacific.
The storm reached sustained winds of 195 miles per hour (315 kilometers per hour), which is above the Category 5 limit of 157 mph (252 kph). In fact, Haiyan remains one of the most powerful typhoons ever to hit the earth.
In their paper, Lin and his colleagues made a case for adding Category 6 to the Saffir-Simpson Hurricane Wind Scale (SSHWS) to accommodate hurricanes with sustained winds above 184 mph (296 kph), such as Haiyan. The scale currently identifies any hurricane with maximum sustained winds greater than 157 mph (252 kph) Category 5, regardless of intensity.
Increased threat of major storms
Lin’s new study analyzed all major hurricanes recorded over the past 40 years, and found that Category 6 hurricanes are becoming more common. There were eight such hurricanes between 1982 and 2011, but 10 between 2013 and 2023. That means that a quarter of the Category 6 hurricanes that have occurred in the past four decades have occurred in the past 10 years.
The study revealed that most of these typhoons occur in warm water areas, the largest of which are in the western Pacific, eastern Philippines and Borneo. The other is found in the North Atlantic, east of Cuba, Hispaniola, and Florida.
The findings also show that these hot spots are getting bigger. For example, the one in the North Atlantic has extended eastward past the northern coast of South America and westward into the Gulf of Mexico. Lin and his colleagues estimate that human-driven global warming is causing a 60% to 70% increase in tropical cyclones and, as a result, the likelihood of Category 6 hurricanes forming.
As the world warms rapidly, it is clear that we are facing a whole new level of tropical storm risk. The debate over whether we should add a Category 6 to the SSHWS—or perhaps even create a new scale—remains unsettled, but this new data underscores the urgency of addressing the growing threat of more severe hurricanes.
