MANATEE -- The last time Florida had an active hurricane season a lot of Manatee County residents believed they were high and dry.
But if you haven’t checked the hurricane evacuation maps in a couple of years, they are worth some study time.
Thanks to new technology that allows for more precise land measurements, nearly a quarter of county residents who weren’t in evacuation areas back then, now are. There are other big changes as well. Nearly 32 percent of people who only had to evacuate in the case of a Category 3 storm, now are advised to leave during a Category 2 storm and 61 percent of people who thought it would be safe to sit out a Category 3 storm, are being told to evacuate.
During the last few years, the Florida Division of Emergency Management has been using lasers mounted to aircraft to record elevations and measurements and are accurate within 6 inches. A high precision GPS system is also mounted on the aircraft to simultaneously record the map locations. Light Detection and Ranging technology known as LIDAR is used by the National Oceanic and Atmospheric Administration and NASA scientists to document topographic changes along the shoreline.
The National Hurricane Center and the National Weather Services validate the data and regional planning councils managed the data collection, Steve Simpson, with the county’s emergency management division, said Tuesday during a joint meeting with the county commissioners and the planning commission.
Manatee County received the new surge data at the end of 2009 to redesign the evacuation zones. The new surge data comes from the Sea & Lake Overland Surge from a Hurricane, known as SLOSH, and is married with the LIDAR data to revise the evacuation maps, which were sent to the Tampa Bay Regional Planning Council where they were reviewed parcel by parcel and then fitted with other maps throughout the region.
The new more precise technology showed that Manatee County has a lower elevation and is more prone to flooding from a hurricane than anyone previously thought, Simpson said.
“In a Category 5 -- the worst case scenario -- the map is a little bloodier,” Simpson said, referring to evacuation zones colored in red on the county’s Coastal High Hazard map.
Simpson said the maps are vital in planning for a hurricane.
The new maps “set the tone for the entire event,” Simpson said. “We are better able to tell how long it will take to evacuate.”
The new Coastal High Hazard maps also will be used in conjunction with the knowledge emergency management officials gained from storms during the last decade. Hurricane Katrina hit land as a Category 3 storm, but it created a Category 5 storm surge. The county is looking at ways to mitigate those kinds of damaging surges before a storm ever hits here, Simpson said.
For John Osbourne, the county’s director of planning, it means that the county should avoid increasing densities in the zones most vulnerable to storm surge and those that will be the most difficult to evacuate based on traffic studies.
“One of the things we have to keep in mind is increasing densities and intensities,” Osbourne said.
“We have to look at densities and intensities for future development and the future land use map. This acts as a cap.”
But John Neal, a developer who attended the meeting, said that the maps reflect the most conservative data for evacuations and that homes built today are sturdier than those built just five years ago.
“We’re talking about where the county wants to grow in the future,” Neal said. “Three-fifths of the population live within 5 miles of a body of salt water.”
Neal has been trying increase density in a proposed development set for Robinson Farm in northwest Bradenton.
The county staff was set to recommend the project until the preliminary information came back on the new hurricane evacuation maps, showing that entire area would have to be evacuated in the event of a Category 1 storm.
Still, Neal won narrow approval from county commissioners for increased density but the project was challenged by surrounding neighbors.
An administrative judge said last month that county commissioners erred when they approved the land use change that tripled the number of homes allowed for construction. Neal is challenging the opinion.
n County commissioners and planning commissioners also reviewed the county’s Industrial Land Use regulations Tuesday as they begin thinking about the county’s comprehensive plan and the future land use map. Much of the discussion focused on creating enterprise zones and on how and where to locate heavy industrial uses.