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
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
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
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.
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