New, up-to-date storm surge data from the National Hurricane Center has thrown a monkey wrench into Tampa Bay's evacuation planning just two weeks before the start of hurricane season.
More residents are likely to be in evacuation zones than ever before. But at this point, emergency management officials from around the bay area said they do not know yet which residents and which areas will be affected.
In Pinellas County, for instance, the new data shows that a worst-case storm surge would be 6 feet higher than previous storm surge predictions.
"We ended up with a much higher storm surge," Pinellas County Emergency Management director Sally Bishop said. "It resulted in a better picture of what the worst-case scenario can be."
Pinellas officials said they will release the county's new evacuation maps on June 1— the first day of the 2017 hurricane season.
Meanwhile, Tampa officials have been told that the storm surge estimates for the city are rising, but they haven't received detailed data yet. Still, they expect the number of people who will have to evacuate ahead of a hurricane to increase.
"It's going to be more," Tampa emergency coordinator Chauncia Willis said.
She said the city is working with the Federal Emergency Management Agency and Midland weather radios to get the word out before a storm: "We're doing all we can to let people know that they are in a position where they need to be prepared."
"Every zone will be expanding slightly under the preliminary models we have examined," Pasco County spokeswoman Tambrey Laine said in an email. "Approximately 8,000 new people are now (going to be) in an evacuation zone. Based on current planning criteria, about 800 would seek shelter during a storm."
That's going to prompt a re-examination of how many shelters the county needs, she said.
Hillsborough County emergency management officials did not respond to a request for comment Friday.
Similar map changes are in the works from Hernando County down around the tip of the state's peninsula at Miami-Dade and back up to Brevard County, according to Brady Smith of the Tampa Bay Regional Planning Council.
Smith said the biggest changes he's aware of are the areas now predicted to face inundation from a Category 1 storm, the weakest one under the Saffir-Simpson classification system. That's a storm with wind speeds of up to 95 mph.
In a state as flat as Florida, where a lot of people have built close to the coast, a higher storm surge means water in places that no one previously expected to flood.
"We certainly had some non-evacuation zones that will be in new evacuation zones," Bishop said. "It has the potential to impact everyone in Pinellas County."
More hospitals, nursing homes and medical facilities will likely be among the additional buildings evacuated should a hurricane hit.
Officials at Johns Hopkins All Children's Hospital in St. Petersburg were briefed on the new surge maps earlier this week, hospital spokesman Roy Adams said.
"We have the information and are evaluating it now," Adams said. He added that it was too soon to say exactly how the hospital will be affected. It has not been in an evacuation zone before.
Tampa Bay area emergency management officials are scrambling to finish the new maps in time for the June 1 start of hurricane season. Some, such as Pasco, won't make that deadline.
Bishop said Pinellas County received the new data from the National Hurricane Center at the end of 2016 and had been working on updating the information "for months."
"Everybody will be able to look up their new evacuation levels by June 1," she said. Bishop said residents and business owners can check the new zones on phone apps, the county website or by calling the office at (727) 464-3800.
John Bennett, an assistant administrator who oversees Pinellas emergency management, said the counties couldn't control when they got the data. He said staffers have worked "diligently" for months to merge the data into complex systems.
"The worst things come from bad evacuation models," he said. "Sure, I would have liked to had this a year ago."
In Hernando County, the emergency management staff has completed its new maps but has not yet brought them to the County Commission for approval. The old maps are in force until the new ones get commission approval, said emergency management director Cecilia Patella. She said the new Hernando surge maps do not significantly change evacuation zones.
The changes in the storm surge calculations were driven by the hurricane center's determination to do a better job of calculating storm surge after Hurricane Isaac in 2012. The Category 1 hurricane killed about 40 people and caused massive and widespread flooding in Louisiana.
The new model looks at a wide swath of Florida as a whole, instead of dividing it up into separate "basins." And for the first time it factors in something called "the Kelvin Wave," which involves the way that a wave bounces off the coastline and then crashes into other waves.
W. Craig Fugate, a Florida native who led FEMA in the Obama administration, said this kind of scramble happens every time scientists produce better storm surge maps. But knowing where a surge might happen is only half the equation.
"You might have to evacuate more people, but you didn't grow any new roads," he said. That information plays into evacuation decisions too, he said.
He also said it's not smart for officials to hastily produce evacuation maps that they are not 100 percent sure are accurate. They still have time to get it right — but not a lot of time.
"June 1 is the start of hurricane season," he said, "but when we see the most danger from hurricanes is when we start playing college football. So don't rush this."
Times senior news researcher Caryn Baird and staff writers Barbara Behrendt, Steve Contorno, Richard Danielson, Kathleen McGrory and Josh Solomon contributed to this report. Contact Craig Pittman at email@example.com. Follow @craigtimes.