MINNEAPOLIS (WCCO) — Hurricane Matthew is expected to make landfall Friday morning in Florida as a Category-4 storm.
It is expected to become a Category 2 by Saturday as it moves up the coast.
So, what do those category numbers mean?
“It’s similar to how we rate tornados,” says Shawn DeVinny, a meteorologist with the National Weather Service in Chanhassen. “All it’s telling you is what the maximum sustained winds are with the hurricane.”
Only three hurricanes to make landfall in the United States in the past 46 years have been a Category 4 or 5: Andrew (1992), Charley (2004) and Hugo (1989).
“We can tell with a Category 4 such as this there’s going to be devastation for structures and trees, and power outages will be widespread and long-lasting,” DeVinny said.
The numbering system — called the Saffir-Simpson scale — was created in 1971. It was developed by and named after a meteorologist and a wind engineer.
DeVinny says the scale is considered the best way to measure the strength of a hurricane because wind speed can tell people the most immediate life-threatening impact.
“It’s like a strong tornado similarly, but in a much more wide area,” DeVinny said.
The category numbers increase in terms of sustained wind-speed severity:
The costliest hurricanes to hit the U.S. are Katrina (2005), Andrew (1992), Ike (2008), Wilma (2005) and Ivan (2004). They were a mixture of Categories 2, 3, 4 and 5.
“You’re comparing a wind speed higher in this case, other hurricanes might be more costly in terms of dollars if there’s a lot worse flooding with those,” DeVinny said.
Superstorm Sandy was not technically a hurricane.