Hurricane categories range from 1 (119km/h winds) to 5 (252km/h and up). There is no Category 6, not even for record breaking storms such as Irma.
Photo by Joe Raedle/Getty Images
A few headlines and memes are going around saying that Irma is a Category 6 storm, or that it should be a Category 6 storm, or that there will soon be a Category 6, as if meteorologists are gathered around tables in some secret meteorologist lair waiting for the exact right moment to add a new category to the Saffir-Simpson scale. In reality, meteorologists are mostly rolling their eyes, like so:
I've been going through my feeds & all I see is fake weather info about #Irma. Folks... there's no such thing as a Category 6 Hurricane ?
— Jim Caldwell (@JimWKYT) September 3, 2017
Dennis Feltgen, a spokesperson for the National Hurricane Center, told the New York Times that there's no need for a Category 6 because Category 5 is already about as bad as we can imagine and plan for.
The scale classifies this level of damage as "catastrophic," Mr. Feltgen said, and "what is left after 'catastrophic' damage?"
Jeff Masters, a meteorologist and hurricane hunter, told Thinkprogress that it might be good to add a Category 6, but not because it's helpful in disaster preparation:
"From a climatology perspective, it would make sense to add a Category 6, to draw attention to the fact that climate change is likely going to make the strongest storms stronger," Masters explained. But "from a practical advisory/warning standpoint, it makes little sense to add a Category 6, since a Category 5 storm is already catastrophic. Having a Category 6 storm would not motivate people to take action to protect themselves any more than having a Category 5 would."
From a preparedness point of view, we already know that hurricane categories don't tell the full story of how damaging a storm is likely to be. Categories are based solely on wind speed and don't predict flooding. For more complete information, it's best to just keep an eye on the National Hurricane Center's forecasts.