You’re likely familiar with the Saffir-Simpson hurricane wind scale, whether you live in a coastal region or not. When a storm develops and intensifies, weather experts often announce, “the storm is currently a Category 1, but it is forecast to strengthen into a Category 3 later in the week.”
Hurricanes are classified using a scale from one to five, based on their sustained wind speeds, with Category 5 representing the highest level of intensity.
However, as climate change contributes to more powerful and frequent hurricanes, some hurricane researchers are arguing in a recent study that the current five-category scale might be inadequate. They suggest the necessity of introducing a Category 6.
Michael Wehner, the lead author of the study and a senior scientist at the Lawrence Berkeley National Laboratory, stated to CBS News, “We discovered that five storms have already surpassed the hypothetical Category 6 threshold, and all of these occurred recently, since 2013.”
The study also highlighted a notable increase in hurricane wind speeds since 1982, suggesting that wind speed records are likely to “continue to be broken as the planet continues to warm.”
Decoding the Hurricane Rating System: The Saffir-Simpson Scale
The existing five-tier Saffir-Simpson scale was initially created in the 1960s and further refined in the 1970s. It categorizes hurricanes based on the maximum sustained wind speed, averaged over a one-minute period at a height of 10 meters (approximately 32 feet) above ground level. This scale is used globally by weather forecasting agencies, including the National Hurricane Center in Florida.
The primary goal of developing this scale was to improve public communication regarding hurricane strength. Here’s a breakdown of the current Saffir-Simpson Hurricane Wind Scale:
- Category 1: Wind speed 74–95 mph. Minimal Damage.
- Category 2: Wind speed 96–110 mph. Considerable Damage.
- Category 3: Wind speed 111–129 mph. Devastating Damage.
- Category 4: Wind Speed 130–156 mph. Catastrophic Damage.
- Category 5: Wind speed 157+ mph. Catastrophic Damage.
Category 6 Hurricane: What Would It Take?
The recent study proposes redefining Category 5 to include hurricanes with maximum sustained winds between 157 and 192 miles per hour. A new Category 6 hurricane would then be designated for any storm exceeding wind speeds of 192 miles per hour.
Currently, storms reaching Category 6 hurricane strength are exceptionally rare.
Typhoon Haiyan, which caused immense devastation in the Philippines in 2013 with wind speeds of 195 miles per hour, would fall into this new category. Four other storms since 2013 would also be classified as Category 6 hurricanes under this proposal. Among them is Hurricane Patricia, which struck Mexico in 2015. The National Hurricane Center reported Patricia’s wind speeds at an astounding 215 miles per hour, marking it as the most powerful hurricane ever recorded. Hurricane Patricia also intensified at an unprecedented rate for tropical cyclones, gaining 105 miles per hour in wind speed within just two days.
Researchers emphasize that rising global temperatures due to climate change increase both temperature and moisture levels, which are key energy sources for hurricanes. This suggests that the frequency of these extremely powerful storms is expected to rise.
Simulations conducted as part of the study, based on various global warming scenarios, indicated that the risk of encountering storms that would be classified as Category 6 hurricanes “has increased dramatically and will continue to increase with climate change.”
The National Hurricane Center, the official body responsible for hurricane category designations for the United States and its territories, has not yet issued a statement regarding the proposed Category 6 hurricane. However, as hurricanes become larger and intensify more rapidly, the discussion around adding a Category 6 hurricane to the Saffir-Simpson scale is likely to intensify as well.
