If – or when – it happens here

Hurricane Harvey swamped entire neighborhoods around Houston, leading to rooftop evacuations that echoed Hurricane Katrina.

The unceasing rain turned highways into boat channels and left thousands of families to sleep in gas stations or trudge through waist-high water to get to a shelter.

"We are seeing catastrophic flooding,” National Weather Service director Louis Uccellini warned.

“You couldn't draw this situation up,” FEMA director Brock Long offered.

But it could have been as bad -- if not worse -- if a hurricane like Harvey struck the Tampa Bay area. 

A University of South Florida study once showed that if a major hurricane hit north Pinellas County, MacDill Air Force Base could get swamped in 13 feet of water.  Thousands of homes in Tampa would see the same kind of flooding we've seen in Houston.

In fact, the Boston-based research firm KCC ranked Tampa Bay as the most vulnerable part of the country.  The Washington Post recently picked up on that, but we've seen other studies that have been telling us that for years.

Ten years ago, the Pinellas property appraiser developed simulations for the county.  After a Category 1 hurricane, much of Dunedin is under water, while Redington Shores gets it from both sides.  And when you bump it up to a Category 2 hurricane, most of Redington Shores gets flooded, Dunedin gets swamped, and flooding sweeps to the Bayfront Tower in St. Petersburg. 

Move up to a Category 3 storm and it takes out 4th Street in St. Pete, while Old Southeast would be reduced to rooftops.  The model shows a Category 4 storm floods the interstate and Tropicana Field.

A Category Five turns the whole downtown blue, as much of the interstate and other major streets go under water -- just as we've seen this week in Texas.

The Tampa Bay Regional Planning Council also worked up a model for a Category 5 storm.  Beyond the flood damage, it projected wind damage would wipe out nearly a half-million homes and businesses.

Tampa Bay has not taken a direct hit from a major hurricane since 1921.

LINK: Pinellas County flood information
LINK: Pinellas County storm surge predictor