‘Category 6’ Hurricanes Might Be on the Horizon, Study Says
Some of the most destructive hurricanes in history have made landfall as a Category 5 storm, defined on the Saffir–Simpson scales as having sustained winds of more than 157 mph. But with more storms in recent years like Hurricane Dorian in 2019 reaching wind speeds of more than 180 mph, some scientists are questioning whether a new Category 6 is necessary.
Researchers explored the idea in a new study published in the Proceedings of the National Academy of Sciences journal. The “open-ended” nature of the Saffir–Simpson scale means “the level of wind hazard conveyed by the scale remains constant regardless of how far the intensity extends beyond [157 mph].”
“This may be considered a weakness of the scale, particularly considering that the destructive potential of the wind increases exponentially,” the study authors wrote. The study, then, was done to “consider how this weakness becomes amplified in a warming world by elucidating the past and future increases of peak wind speeds in the most intense tropical cyclones.”
By creating a hypothetical Category 6 for storms with sustained winds greater than 192 mph, the researchers found that we’ve already reached that territory, and it’s only going to get worse. “A number of recent storms have already achieved this hypothetical Category 6 intensity and based on multiple independent lines of evidence examining the highest simulated and potential peak wind speeds, more such storms are projected as the climate continues to warm,” they wrote in the paper.
By this metric, the Atlantic Basin has never experienced a Category 6 storm; the closest recorded winds were during Hurricane Allen in 1980 at 190 mph. The Pacific, meanwhile, has seen strong storms such as Hurricane Patricia in 2015, the most powerful tropical cyclone ever recorded worldwide with sustained winds of up to 215 mph.
The question of extending the Saffir–Simpson scale to Category 6 isn’t new. Some believe it’s unnecessary because anything above Category 5 is going to be catastrophic regardless of the preparations taken. Former National Hurricane Center director Robert Simpson, for whom the scale is named, said in a 1999 interview that the scale stops at Category 5 since winds that high would “cause rupturing damages that are serious no matter how well it’s engineered.”
The study authors warn that the worsening nature of storms due to a warming planet might make a new category necessary. Study co-author Jim Kossin said that the open-ended nature of the current Category 5 designation means that it’s “becoming more and more inadequate with time because climate change is creating more and more of these unprecedented intensities.”
Regardless of where you live, it feels like no one is safe from the fear of living through “The Big One.”