Hurricane Milton Shows How a Storm’s Category Doesn’t Tell the Full Story

“Pressure is easier to measure, easier to forecast, and matters more for damage, but NHC, through inertia, they’re tied to the current system, and they think changing it would confuse people, unless there’s a silver bullet,” Schreck says. “And there is no silver bullet.”

No single number can capture all hurricane impacts. That was demonstrated by Helene, which made landfall in Florida as a Category 4 but unleashed “biblical” rainfall hundreds of miles inland in Georgia, South Carolina, and North Carolina. The storm killed more than 200 people, half of them in western North Carolina, where mountain valleys channeled the rainfall into devastating floods. The impact was compounded by a tropical storm that showered the Carolinas with historic rainfall two days before Helene.

Before Helene hit, forecasts compared its rainfall to hurricanes Frances and Ivan, which brought up to 18 inches of rain to some parts of North Carolina in 2004, triggering 400 landslides and killing 11. They also cited a record-setting flood in 1916, warning that the “impacts will be life-threatening.” The storm two days before Helene was described as a “once-in-a-thousand-year event.” But the fact that so many people died nonetheless shows a “communication disconnect” between our storm warning system and the public, says Schreck, who lives in Asheville and was without power and water for days.

He’s also helped develop an “enhanced rainfall” scale, where a Category 5 event pours five times as much rain as an area would get once every two years on average, a Category 4 dumps four times as much, and so on. The predicted rainfall would have made Helene a Category 3 extreme rainfall event in the mountains of North Carolina rather than just a Category 4 hurricane on the coast of Florida.

“Nobody knows what 500 or 1,000 years means. It’s basically inconceivable,” Schreck says of probability-based systems. “So it’s saying, take the biggest event you can remember and multiply it by three.”

Not everyone will evacuate even for a major storm, however, especially in a hurricane-weary state like Florida. More than a million people were under an evacuation order there for Milton, with Governor Ron DeSantis urging residents to “run from the water” and the mayor of Tampa warning those who don’t are “going to die.” But one mother named Amanda Moss went viral with TikTok videos saying she didn’t have the money for flights and hotels to evacuate her husband, mother-in-law, six children, and four French bulldogs from Fort Meyers, which faces up to 12 feet of storm surge. In the comments, some other users said they were also staying put, arguing they couldn’t get off work or were worried about gas shortages.