GULFPORT - Beginning Nov. 18, South Mississippians can go to the Internet and pinpoint flood elevations recommended for construction on coastal property.

FEMA is using satellite technology to generate maps showing new advisory flood elevations, lot by lot. Maps also will show Katrina's tidal surge, which was even higher.

Quite frankly, in terms of hurricane storm surge, nothing compares to Hurricane Katrina. Not even close," Todd Davison, FEMA's mitigation director for this region, told the Sun Herald on Wednesday. He said the surge from Hurricane Camille in 1969 was 10 feet or more lower.

Katrina's highest recorded surge was 35 feet, on the Mississippi Sound in west Pass Christian.

While new advisory flood elevations are lower than Katrina's surge, they are 3 to 8 feet higher than current flood elevations in the three Coast counties.

FEMA is urging Coast cities and counties to require that residents build to the new advisory elevations, designed to minimize loss of life and property.

Governments that fail to adopt the elevations could jeopardize millions in federal dollars, including grants to homeowners for elevating their houses and funding to reconstruct public buildings at safer heights.

"These advisory maps are trying to advance what is the inevitable," Davison said.

Homeowners who build to the higher elevations could see discounted insurance rates.

In 18 months, FEMA expects to finish tweaking new flood elevations, bring them back to local governments for public review, then publish final insurance rate maps.

Local governments must then adopt the new maps or be dropped from the National Flood Insurance Program, started in 1968. Residents who rebuild at current elevations will pay rates from those maps.

The 1982 maps currently in use were developed using old data and technology. Davison said the budget to update maps was very limited until 2003, when Congress increased it six- to seven-fold as the intensity and frequency of coastal storms emphasized the need for better information.

FEMA was working on new Coast maps when Katrina hit. The agency produced them as quickly as possible so rebuilding could begin in South Mississippi. Developing the advisory elevations created debate within the agency, he said. "

No. 1 is timing," Davison said, "We have never tried to do anything this fast before and hold the science together."

The elevations show how high above mean sea level a building should be raised to minimize flood risk. There is a 1 percent chance in any given year that water will reach flood elevations.

"It's all about the elevation," Davison said. "The higher you go, the safer it is."