A handful of super powerful tropical storms in the last decade and the prospect of more to come has a couple of experts proposing a new category of whopper hurricanes: Category 6.
Studies have shown that the strongest tropical storms are getting more intense because of climate change. So the traditional five-category Saffir-Simpson scale, developed more than 50 years ago, may not show the true power of the most muscular storms, two climate scientists suggest Monday in a study in the Proceedings of the National Academy of Sciences.
They propose a sixth category for storms with winds that exceed 309 kpm (192 mph).
Currently, storms with winds of 252 kph (157 mph) or higher are Category 5. The study's authors said that open-ended grouping doesn't warn people enough about the higher dangers from monstrous storms that flirt with 322 kph (200 mph) or higher.
Several experts told The Associated Press they don't think another category is necessary. They said it could even give the wrong signal to the public because it's based on wind speed, while water is by far the deadliest killer in hurricanes.
Since 2013, five storms — all in the Pacific — had winds of 192 mph or higher that would have put them in the new category, with two hitting the Philippines.
As the world warms, conditions grow riper for such whopper storms, including in the Gulf of Mexico, where many storms that hit the United States get stronger, the study authors said.
“Climate change is making the worst storms worse," said study lead author Michael Wehner, a climate scientist at the Lawrence Berkley National Lab.
It's not that there are more storms because of climate change. But the strongest are more intense. The proportion of major hurricanes among all storms is increasing and it's because of warmer oceans, said University of Miami hurricane researcher Brian McNoldy, who wasn't part of the research.
From time to time, experts have proposed a Category 6, especially since Typhoon Haiyan reached 315 kph (195 mph) wind speeds over the open Pacific. But Haiyan "does not appear to be an isolated case,” the study said.
Storms of sufficient wind speed are called hurricanes if they form east of the international dateline, and typhoons if they form to the west of the line. They're known as cyclones in the Indian Ocean and Australia.
The five storms that hit 309 kpm (192 mph) winds or more are:
- 2013's Haiyan, which killed more than 6,300 people in the Philippines.
- 2015's Hurricane Patricia, which hit 346 kph (215 mph) before weakening and hitting Jalisco, Mexico.
- 2016's Typhoon Meranti, which reached 315 kph (195 mph) before skirting the Philippines and Taiwan and making landfall in China.
- 2020's Typhoon Goni, which reached 315 kph before killing dozens in the Philippines as a weaker storm.
- 2021's Typhoon Surigae, which also reached 315 kph before weakening and skirting several parts of Asia and Russia.
If the world sticks with just five storm categories “as these storms get stronger and stronger it will more and more underestimate the potential risk,” said study co-author Jim Kossin, a former NOAA climate and hurricane researcher now with First Street Foundation.
Pacific storms are stronger because there's less land to weaken them and more room for storms to grow more intense, unlike the Gulf of Mexico and Caribbean, Kossin said.
