Hurricane Fears New Storm Study Has Bad News

Article excerpt

A sneak peek at a new storm study due next year shows some parts

of Jacksonville would be under more than twice as much water

than previously believed if the city were hit by a powerful

hurricane.

Duval County's current hurricane evacuation plan is based on a

1988 study whose best and most accurate information is centered

on the South Georgia coast.

The Northeast Florida Regional Planning Council is in the early

stages of compiling a report that will deliver much more

accurate information on storm surge -- the dome of water that is

responsible for 90 percent of hurricane deaths.

At the request of the Times-Union, the planning council provided

an early look at what the new surge study due for next year's

hurricane season may reveal. Ten of 11 points picked at random

in Duval County show storm surges higher -- some much higher --

than indicated under the previous study.

The results will prompt disaster planners to rethink evacuation

patterns and shelter requirements.

But don't panic. The data is preliminary and should be viewed

with caution, warns Jeff Alexander, a senior planner for the

planning council.

In a Category 4 hurricane -- like hurricanes Andrew and Hugo

-- the old storm surge study estimated the intersection of San

Pablo Road and Beach Boulevard would be hit with a 3.1-foot

surge of water.

The new study shows the intersection under 7.9 feet of water.

"That's the difference between water up to your knees and water

over your head," Alexander said.

The anticipated water levels for San Pablo Road at Atlantic

Boulevard also change -- the old estimate was less than a foot

of water in a Category 4 hurricane. The new estimate is 5.6 feet

of water.

Both roads are major evacuation routes from the beaches.

At the SeaWalk Pavilion on Jacksonville Beach, the surge

estimate for a Category 3 hurricane was 1 foot in the 1988 study

and 4 feet in the new study.

MORE DATA NEEDED

Alexander warned the council won't be able to draw any

conclusions about the data until the storm surge atlas is

completed in early 1998. That means it will be available for

disaster planning purposes in the council's seven-county zone by

next hurricane season.

"One generalization you can make, we're able to identify where

the water's going with a great deal more accuracy," he said.

A complete plan, including a population and transportation

analysis, shelter needs and a behavioral study, is scheduled for

completion Jan. 1, 1999.

The old study was assembled by the U.S. Army Corps of

Engineers. The most accurate information in the study was for

the Brunswick, Ga., area.

The new study was made possible by a $360,000 state grant, with

the best information centered on Northeast Florida and the St.

Johns River.

Hopes are the study will give a much more accurate picture of

flood zones in heavily populated areas farther south alongside

the St. Johns River.

The heart of the study is data provided by the National Oceanic

and Atmospheric Agency .

Next comes the tedious part.

NOAA calculates storm surge in a particular area in a

particular grid, but does not take into account land elevation.

It is up to the planning council staff to compute the surge

level by subtracting the ground elevation from NOAA's surge data

to figure if the area in a particular grid would be underwater

in a hurricane.

To give an idea of how much more accurate the new study will

be, the old study calculated storm surge in 12 1/2-square-mile

grids. …