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Elevation? On signs, it's mostly estimation

Published Aug. 28, 2005

The words on the metal road sign in Allendale say: "37 feet above sea level." Candy Lenderman remembers the sign giving her comfort when a hurricane forced her to evacuate to her parents' home, four blocks away.

But it turns out that sign and others like it are wrong. Some of them are really wrong.

One in downtown St. Petersburg is off by 23 feet. The one in Allendale is off by 4 feet. One in front of Woodlawn on 22nd Avenue N is off by 9 feet.

"What did they do, guess?" asked Lenderman, a retired schoolteacher.

Well, not exactly. The signs are relics of the days when the city of St. Petersburg had a civil defense department that mostly concentrated on protecting against nuclear war. The agency went on to become known as emergency management; now it's charged with protecting the public from natural disasters. Like hurricanes.

Why the signs are so inaccurate is something of a mystery.

Jim Barca, the city's former emergency management coordinator, said he recalls some of them already in place when he took over the city's civil defense agency in 1981 or 1982. Barca, who retired in 2000, said he remembers coordinating with other city officials in the 1980s to put in additional signs, possibly a dozen or more, mostly on evacuation routes.

They were meant to inform residents of sea level elevations so they would know the city's safest areas. Barca said he thought the numbers for the sea levels came from the city's engineering department.

Michael J. Connors, the city's director of engineering, determined that at least some of the signs were put in April 15, 1989, in locations provided by the civil defense department. Only a handful of the signs remain.

"Unless there's something in the record to keep them there, we will remove them because they are inaccurate," Connors said.

The most inaccurate sign is downtown, on Fifth Avenue N between Third and Fourth streets. It says the area is 15 feet above sea level; it's really 38 feet above sea level.

The sign at 22nd Avenue N and 12th Street N says it's 39 feet above sea level; it's really 48 feet. The one near Allendale at 38th Avenue N and Dr. Martin Luther King Jr. Street says 37 feet above sea level; it's really 41 feet. The correct numbers are provided by the county, which paid for high-tech Light Imaging Detection and Ranging, a process that uses lasers to measure topography from an airplane.

The elevation signs are meaningless today because of the way emergency managers handle evacuations. They review the strength of a hurricane and compute how far above sea level it will push the storm surge, then evacuate zones of residents. The zones are provided to residents in color-coded hurricane guides, handout maps and Web sites.

For the record, anyone 25 feet above sea level would not get storm surge even in the worst-case scenario, if a Category 5 hurricane hit between Clearwater and Palm Harbor, said Gary Vickers, director of Pinellas County's emergency management. That's why there are areas in Pinellas that are never evacuated.

Those same homes, though, are subject to hurricane damage by wind, and evacuations never take that into account.