A bigger radius of maximum wind can produce much more storm surge.

What the FAA says is that within a 500-foot radius of that wind sensor, the maximum object height has to be 15 feet below that wind sensor.

The thing that kills people isn't so much the wind, ... It's the storm surge. I'm worried that on that peninsula that sticks out into the ocean, there's going to be grave loss of life. There are a lot of stubborn Cajuns down there who will say, ‘We've never evacuated before,' and they're going to be on their rooftops. I'm really worried about Gulfport and Biloxi, (Miss.), too.'

We expect the impacts to South Florida to begin late [Thursday] afternoon with squalls and surge.

What we are really concerned about is the storm surge and tremendous rains,

It doesn't take much to flood those islands. With a storm surge of 4 to 6 feet, it's still going to cover a great deal. Depending on how well the homes are built and how old they are, they can get flooded out pretty fast.