The Saffir–Simpson hurricane wind scale, developed in the early 1970s, ranks hurricanes from Category 1, which means winds of 74-95 mph, to Category 5, which covers winds of 157 mph or more.
Since each category covers a range of wind speeds, it would appear that once wind speed reaches 190 or 200 mph, the pattern may call for another category. Last season saw two Category 5 hurricanes, Irma and Maria, with Irma reaching 180 mph. And in 2015, off Mexico’s Pacific coast, Hurricane Patricia achieved a freakish sustained wind speed of 215 mph.
“If we had twice as many Category 5s — at some point, several decades down the line — if that seems to be the new norm, then yes, we’d want to have more partitioning at the upper part of the scale,” Hall said. “At that point, a Category 6 would be a reasonable thing to do.’’
Many scientists and forecasters aren’t particularly interested in categories anyway, since these capture only wind speed and not the other dangers posed by hurricanes.
“We’ve tried to steer the focus toward the individual hazards, which include storm surge, wind, rainfall, tornadoes and rip currents, instead of the particular category of the storm, which only provides information about the hazard from wind,” said Dennis Feltgen, spokesman for the National Hurricane Center. “Category 5 on the Saffir-Simpson scale already captures ‘catastrophic damage’ from wind, so it’s not clear that there would be a need for another category even if storms were to get stronger.”