In the Danger Zone
Originally published in the June 9, 2007, Mobile Press-Register, this article explains how federal flood maps, which are supposed to indicate areas that will be seriously affected by storm surges, are dangerously off the mark, leaving thousands of Gulf Coast residents vulnerable.
Image: In the Danger Zone
Steve Myers

New Press-Register research indicates that many coastal Alabama homes are vulnerable to catastrophic hurricane damage due to errors and obsolete data in Federal Emergency Management Agency flood maps.

As a result, Alabama homes are as vulnerable to widespread flooding as their neighbors in Mississippi and Louisiana, where Hurricane Katrina's massive storm surge in August 2005 destroyed entire neighborhoods. That hurricane exposed problems with FEMA's flood maps, and, consequently, with the building and insurance requirements based on those maps.

While not impossible, it's incredibly unlikely that there would have been three 100-year floods here in 36 years—in fact, the probability is just 0.5 percent.

Many Katrina victims didn't realize their houses could succumb to a hurricane storm surge, so they never bought flood insurance. After the storm, thousands of coastal Mississippi and Louisiana homeowners found themselves with nothing but skeletal remains of their homes and the painful realization that they had misjudged their risk.

Throughout coastal Mobile County, Katrina's record-level flooding exceeded the federal government's predictions for a 100-year storm—a storm that, in theory, is so unusual that it has only a 1 percent chance of occurring each year, and over the long term should occur only once a century.

Yet the Press-Register's research indicates that Katrina's surge impact in Alabama wasn't that unusual when compared to other hurricanes that affected Mobile's coastline in the past four decades.

In what appears to be the first attempt to validate federal flood maps in Alabama, the newspaper collected 36 years of flooding data—1969 to 2005—and checked them against flood maps. The data indicate that the 100-year level has been exceeded in large stretches of Mobile County twice in the 36 years, by Katrina and 1979's Frederic, and three times in Baldwin County, by Katrina, Frederic and 2004's Ivan.

The upshot: Flooding levels considered by FEMA to be once-in-a-century events may actually be occurring at a rate of six to nine times per 100 years.

While not impossible, it's incredibly unlikely that there would have been three 100-year floods here in 36 years—in fact, the probability is just 0.5 percent.

"What that means is, there's a 99 percent chance it's wrong," said Joe Suhayda, a retired Louisiana State University professor with extensive experience in storm surge modeling. He is now working as a consultant, reviewing changes to flood elevations in Louisiana.

Predicting a once-in-a-century storm isn't just an academic exercise. Local governments use FEMA's 100-year estimate to set building requirements in the flood plain, while mortgage companies refer to FEMA flood maps to determine whether a property requires flood insurance.

FEMA is responsible for both the National Flood Insurance Program and the flood maps used to set the program's premiums. Such coverage is separate from homeowners' insurance, which is sold by private companies and doesn't cover storm surges.

'A huge gaffe'

The Press-Register investigation indicates that FEMA's official 100-year flood plain along miles of coastal Alabama covers too small of an area. As a result, people who live outside that official boundary may be more vulnerable to surge damage than those inside.

Unlike people within the 100-year flood plain—who are usually required to buy flood insurance and elevate their homes—people outside that zone don't have to buy flood insurance and can build the living spaces of their homes at ground level.

Yet historical data examined by the newspaper indicate that the storm surge can rise just as high outside Alabama's coastal flood plain as within. Most people never know.

"That's a huge gaffe," Suhayda said.

People living in older homes constructed before building regulations were established are at risk as well as those in new homes that adhere to the minimum standards.

The trouble spots include the Baldwin beaches and the western shore of Mobile Bay—the most desirable and in some cases the most densely populated areas of southwest Alabama. And builders continue to construct homes in those areas without accounting for the flood damage of the past three decades.

In Mobile County, developers have proposed two major residential projects on the bay near Fowl River, while Mobile's city Planning Commission has routinely approved subdivisions within flood-prone areas.

In Baldwin, people are rebuilding and constructing new homes around Little Lagoon in Gulf Shores, including an area north of the lagoon that is outside the official flood plain but has experienced damaging surges.

Old science

The problem with FEMA's flood maps, according to scientists and federal officials, is that they are based on outdated science more than 20 years old. In those 20 years, scientists have collected extensive storm data, developed new computer tools and dramatically improved their ability to predict hurricane surges.

Official flooding predictions, however, have remained static. Even new FEMA flood maps for coastal Alabama, which are being finalized now with minor revisions, don't account for any of the storms that have struck since the early 1980s.

That's precisely the same situation that Mississippi was in before Katrina. There, building requirements had never accounted for damage done by Camille in 1969. Experts say those lax building standards were responsible for much of the Katrina damage years later.

Immediately after Katrina, FEMA decided to revamp flood maps in Mississippi and Louisiana. Scientists involved in the effort say the new predictions for 100-year flood elevations are significantly higher than before, largely because researchers are using more recent data and more sophisticated scientific modeling.

The increased elevations mean that the high-risk area will be expanded and that homes will have to stand higher off the ground.

Suhayda said Alabama's heights probably also would rise if its maps were revamped in the same way, but FEMA did not include Alabama in its post-Katrina remapping. FEMA officials said flooding here wasn't unusual and that damage from the storm didn't match the devastation to the west.

FEMA knew that rebuilding in Mississippi and Louisiana would not wait on its new maps there, so the agency quickly issued interim flood elevations and urged local governments to adopt them. The differences were substantial.

In Hancock County, building heights went up 6 to 8 feet. In Jackson County, they went up 3 to 5 feet. About 90 percent of the city of Pascagoula now lies in the 100-year flood plain, triple the area that was included before FEMA issued its advisory flood elevations, according to the city's chief building official.

But in Alabama, homes being rebuilt after Katrina can stand several feet lower than in Mississippi.

Before Katrina, flood elevations—and minimum building requirements—were consistent across the Alabama-Mississippi line. Now the minimum building height drops from 21 feet above sea level in one part of southeast Jackson County, Miss., to 16 feet in Mobile County.

Although FEMA officials told the Press-Register that people rebuilding in Alabama should be fine if they stick with existing standards, some local governments believe otherwise. Mobile and Baldwin counties and Gulf Shores and Orange Beach raised their building requirements after inspecting Katrina's and Ivan's damage to recently built homes.

Those requirements address new construction and renovation within the local flood plain, but do not affect outside areas, where building requirements are minimal.

FEMA says that money will be available in fall of this year to begin fully remapping coastal Alabama. New maps could be ready by 2010 at the earliest, according to one agency administrator, although some local officials believe the process will take longer, based on their experiences in dealing with minor map changes.

In the meantime, construction will be guided by a new set of flood maps that are very similar to the maps that have been around for years. People will use those maps to decide whether they should buy flood insurance, even though scientists and FEMA agree that the maps don't paint a true picture of risk.

While the federal government encourages people on the coast to build higher than the minimum and buy flood insurance even if its not required, numerous interviews indicate that people usually do only what they have to do.

Some people complain that they can't afford to elevate their homes, and affordable-housing advocates believe that stiffer requirements will force poor and working class families from their home communities.

Increasingly, however, scientists and flood plain managers say that people shouldn't live in low-lying areas without being prepared for a major hurricane.

"The point is to make people build right or just don't insure them," said John Eringman, who recently retired from the U.S. Army Corps of Engineers as a flood plain coordinator.

Even with Ivan and Katrina striking nearby, Mobile and Baldwin counties have largely dodged catastrophic hurricane damage in recent decades. All that time without a direct hit may have dulled people's memories of just how bad a major hurricane can be.

Katrina was the closest thing to a wake-up call for coastal Alabama, despite making landfall about 70 miles west. The hurricane caused record flooding in swaths of Mobile County with a surge that was roughly equivalent to a Category 2 storm, according to surge estimates on federal evacuation maps.

"The real overarching question is, are we going to have a hurricane-resistant society along the coast," asked University of South Alabama professor Scott Douglass, "or are we going to be unnecessarily hammered by big storms?"

Douglass, who specializes in coastal engineering, noted that coastal Mississippi was devastated by Camille in 1969 and then Katrina, "two storms with 20-foot surge over the last 40 years. You can't say it's not going to happen again. It's only a question of when."

(Press-Register Staff Reporter Dan Murtaugh contributed to this report.)

Originally published on June 9, 2007 in the Mobile Press-Register. Courtesy of the Press-Register 2007 © All rights reserved. Reprinted with permission.