A history of flooding

Storm data, however, fail to support the idea that Frederic was a hurricane so intense that it would come around less than once in a century, as claimed in FEMA's current Mobile County Flood Insurance Study. That study shows the scientific backing for flood predictions reflected on federal flood maps.

Over a 36-year period, two storms—Frederic and Katrina—have pushed water above the predicted 100-year level on Dauphin Island and the southern half of Mobile Bay's western shore. (Katrina's flooding extended farther north and inland than any other storm in the Press-Register's research.) Moreover, several other storms—Camille, Ivan in 2004, Georges in 1998, Elena in 1985—also surpassed the 100-year prediction in a few areas.

Baldwin County has a similar track record: Three storms in 36 years, Frederic, Ivan and Katrina, flooded land on the Gulf beyond the 100-year level.

Such storms are etched into the collective memory of the Mobile area, serving as benchmarks when people assess the latest hurricane brewing offshore. Yet even storms that left little impression in Alabama have exceeded the government's expectation for a once-in-a-century storm.

For instance, although 1995's Hurricane Opal struck Santa Rosa Island, Fla., it pushed water more than 16 feet above sea level—about 5 feet above the 100-year level—and inundated Baldwin areas outside the official flood plain.

But FEMA's Baldwin County Flood Insurance Study, revised in 2002 and again this year, downplays Opal's impact in Alabama, simply contrasting it with the 14- to 21-foot surge near landfall in Florida. "Baldwin County experienced substantially lower surge levels," the report states.

Such is the disconnect between flood insurance studies and post-storm surveys of high-water marks.

The insurance studies are updated periodically, but continue to carry forward old assumptions and data. Meanwhile government employees and contractors fan out after major storms and record flood levels and damage, many of which seem to cast doubt on the 100-year predictions.

For example, federal employees and contractors have returned several times to note flooding at the intersection of Cabana Beach Road and Pompano Way on Fort Morgan Peninsula.

According to the flood map of the area, water will reach 8 feet above sea level there every 100 to 500 years, on average.

But after Frederic, surveyors recorded two high-water marks of 12 feet. Opal caused 11.85 feet of flooding in 1995. In 1998, Georges struck near Biloxi and shoved 12.4 feet of water on the Fort Morgan beach. Then Katrina flooded the area to 11 feet.

"If it's been exceeded four times in places in the last 50 years, we're nowhere near what the correct 100-year storm level is," said Scott Douglass, a coastal engineering professor at the University of South Alabama.

The Press-Register found similar clusters at Coden, Bellefontaine, Alabama Port, Fowl River, West Beach and the central beach of Gulf Shores, the north shore of Little Lagoon, Perdido Key, Cotton Bayou and Dauphin Island.

There could be other problem areas, but the Press-Register's research was limited by the availability of high water mark surveys. While the government reliably collects such information near landfalls of major hurricanes, the data can be spotty for lesser storms and areas farther from landfall, including creeks and rivers that can channel storm surge well inland.

Several scientists reviewed the Press-Register's findings, including Q. Jim Chen, a Louisiana State University professor who specializes in coastal flooding and storm surge modeling.

Chen said he was surprised at how poorly flood predictions correlated with actual high-water marks. For instance, though Dauphin Island was on Ivan's weaker, west side, two marks exceeded the 100-year level and one was recorded outside the flood plain.

He said he would be concerned if a third to half of the high-water marks in an area exceeded the 100-year level. According to Press-Register research, about 40 percent of high-water marks in Alabama for Frederic, Ivan and Katrina exceeded the 100-year level or were recorded outside that flood plain. (The newspaper research didn't include marks influenced by waves.)

Questions have been raised previously about FEMA's flood predictions for southwest Alabama. In a report for the agency summarizing Ivan's impact in Baldwin County, an engineering firm noted how many high-water marks exceeded the 100-year level.

"An evaluation is needed of the recurrence intervals of the surge conditions across the area," the report stated. "Preliminary evidence suggests that much of the area that experienced the most severe surge conditions was exposed to more than (FEMA's predicted) 100-year conditions."

Local government officials in both counties reviewed the Press-Register's research and said it confirms what they had long suspected: The flood maps are unreliable.

In fact, until FEMA's 2002 Baldwin County Flood Insurance Study, the federal government predicted that some areas of the beach would not be subject to the damaging effects of waves--which any viewer of The Weather Channel knows is a mistake.

"As far as FEMA was concerned, you could build on a shallow foundation on the coast," said Lannie Smith, the head building inspector for Orange Beach, referring to thin or weakly anchored foundations prone to failure during storms. "It was just wide open."

Some local governments have dealt with excessive hurricane flooding by raising their minimum building requirements above FEMA's 100-year height. That covers new construction and renovation within the 100-year flood plain, but has no effect beyond it.

So while people within the flood plain build higher, those just outside remain on the ground.

Most recent development in Gulf Shores, for example, has occurred outside the flood plain, where the city does not regulate elevations to deal with storm surge, according to Brandan Franklin, the city's chief building official.