Are there category 6 hurricanes, have there been any in the history of the USA?

Hurricane Milton has weakened somewhat as it approaches the Gulf Coast of Florida. But it is still forecast to make landfall as a major hurricane, Category 3 or higher.  The tropical cyclone, which formed last week over the western Gulf of Mexico stunned meteorologists and the public alike when it rapidly strengthened from a tropical storm to a Category 5 hurricane in just 36 hours.

However, the Saffir-Simpson scale, which is used to rank the intensity of hurricane winds, only goes up to Category 5 and the threshold for that level is when a storm sustains winds of 157 mph. Milton sustained winds of 180 mph at one point, which has been a suggested threshold to classify a hurricane as a Category 6.

And while such powerful storms are rare, Milton is not the first to reach such levels. This has prompted calls for a Category 6 classification, and even a Category 7.

Are there category 6 hurricanes, have there been any in the history of the USA?

The Saffir-Simpson Hurricane Wind Scale currently has five categories of hurricane strength. Storms get baptized with a name from a predetermined list when its winds surpass 39 mph. It becomes a Category 1 hurricane once it sustains winds of at least 74 mph. Then as it gains strength, it moves progressively up the scale but the span of range between each category is not linear. Nevertheless, the National Hurricane Center says, “damage rises by about a factor of four for every category increase.”

Jeff Masters, a hurricane scientist who worked with the NOAA Hurricane Hunters, is one of the people arguing that there should be a Category 6 ranking, even a Category 7. While Category 5 storms are rare, more powerful storms are becoming more common. Since 1924, there are an estimated 42 hurricanes, including Milton, that have become a Category 5 storm in the Atlantic Basin, but only four have made landfall while still packing winds above 157 miles per hour.

Masters, says that the threshold for a Category 6 hurricane should start at 180-185 mph. Hurricane Dorian, which struck in 2019 would have qualified for that status slamming into Great Abaco Island in the Bahamas packing 185 mph winds.

With the lower threshold seven hurricanes could have been categorized as a Category 6 storm including Mitch of 1998, Rita of 2005, Irma of 2017, which hit top wind speeds of 180 mph; Dorian of 2019, Labor Day of 1935, Gilbert of 1988, Wilma of 2005 with sustained winds of 185 mph; and Allen of 1980 whose winds clocked in at 190 mph.

As for a possible Category 7, Masters thinks the threshold for sustained winds should be between 210 and 215 mph. There is only one known hurricane in the world that would have met that status, Hurricane Patricia of 2015. The tropical cyclone off the coast of Mexico reached sustained winds of 215 mph. Fortunately, it lost strength before it made landfall still as a major Category 4 hurricane, with winds of 150 mph.