Filling Coastal Zones With People Complicates Hurricane Evacuation

May 6, 2008

The Tampa Tribune–May 5, 2008

Signs of increasing risk along the shore are apparent from space. Satellite photos released by NOAA show steady development of coastal lands between Texas and North Carolina.

The space and weather agency lists Hillsborough County among the top 10 areas in the South in the amount of visible new development.

A closer look confirms that the trend picked up in the high-altitude photos and is cause for concern. The Hillsborough coast, south of the Alafia River and west of U.S. Highway 41, has grown by 71 percent from 2000 to 2007. The more people who live in zones that must be evacuated when a hurricane approaches, the longer the time it will take to get everyone to either safe territory or a shelter.

The 16-hour clearance time urged by the Florida Department of Community Affairs may be too ambitious a standard for the congested, densely populated Tampa area, but it’s a good number to keep in mind when approving new subdivisions near sea level.

The last time the Tampa Bay area saw 16-hour evacuation times was probably around 1921, the last time a hurricane hit Tampa, says Betti Johnson, the region’s principal planner for emergency management.

"I think we can get people to high ground in 16 hours, but not to where they want to go," says Johnson. Her agency, the Tampa Bay Regional Planning Council, works with county emergency preparedness offices and other agencies to monitor growth and traffic congestion.

The population at risk from a minor storm in Hillsborough is expected to increase by 12 percent by 2011.

The census tracts along the coast in southern Hillsborough have grown at a much faster rate. Nearly 15,000 people have moved in over the past seven years. The southern tip of the Tampa peninsula has grown by another 3,300 people.

When traffic fleeing southwest Florida is added to the total Tampa Bay evacuation number, estimated clearance times for major storms increase, in the worst cases, to over 100 hours. That means some people need to start evacuating when the storm is more than four days away.

"We’ll never have 100 hours of lead time, or even 55," Johnson says. "For emergency planning purposes, outside 24 or 48 hours, people just aren’t going to evacuate."

Johnson outlines a realistic time schedule: At 48 hours, a hurricane watch is issued. Local governments start paying close attention to the storm’s strength and track. Police forces, the Red Cross and school boards began to prepare.

"At 36 hours, we have to make a decision," she says.

The estimated clearance times for the strongest storms, which will frighten many people to also abandon high, relatively safe neighborhoods, is between 65 and 74 hours. That’s assuming police turn all traffic on the interstates in the same direction. That’s nearly three days.

"The issue is increased density," says Tom Pelham, director of the Department of Community Affairs. "The 16-hour rule wouldn’t affect what’s already allowed. But why should the public continue to subsidize heavy concentrations of development in hazardous coastal zones?"

It’s a question the Legislature did not answer. Lawmakers refused to approve his 16-hour recommendation for new development.

Tampa area residents must understand that actual evacuation times for big storms could be longer than the time it takes a storm to get here. If you dawdle, you’ll get a great view of the storm through your windshield.