Proposed rating
scale forecasts hurricane damage
September 22, 2005
College Park, MD -- Researchers have designed a rating system that forecasts
with greater detail what will happen when a hurricane moves to land. Called the
Hurricane Impact Scale, it takes into account the interaction of the hurricane
with the coast. On this scale, Hurricane Rita, projected to hit the Texas coast
on Saturday, merits at least a nine out of possible 15.
The National Hurricane Center currently rates hurricanes using the Saffir-Simpson
scale. Hurricane Rita is rated at Category 4 today. Meteorologists say the Saffir-Simpson
scale is good at rating a storm's wind speed out in the ocean, but doesn’t
give the best idea of what to expect in the aftermath.
Geologists Robert Young of Western Carolina University, Cullowhee, NC, and
David Bush of the State University of West Georgia in Carrollton, have proposed
a new scale that categorizes hurricanes using three factors: the storm surge,
which is the height of the water pushed towards shore by strong winds; how much
coastline is impacted by the heightened water level; and the wind speed. The
storm surge is a new factor in hurricane scale prediction - it helps show the
location of the most damage after a hurricane.
The hurricane impact scale, nicknamed HIS, rates hurricanes from 3 (low) to
15 (high).
The scale is still being perfected, but Bush anticipates presenting more information
at next month's annual meeting of the Geological Society of America. a classification
of the geologic setting of the coast. Based on the width of the continental shelf
and the way the shoreline curves, Bush and Young mathematically rate which areas
of the coast are likely to have amplified storm surge - in areas with a wide
shelf, and coasts curved inland -- or diminished storm surge -- in areas where
the continental shelf is narrow, and the coast is straight or bends out.
What rating would they give to Hurricane Rita? "It really depends on
where it makes landfall, " Bush said. "We are looking at the potential
for a really maximum storm surge. And Rita is a huge storm, so a great stretch
of shoreline will be affected. On our scale, this could be something greater
than a 9 for sure (out of 15) and possibly 12 or greater depending on the category
of the storm at landfall."
He said that if it hits as a strong 3 or 4 and the center of the storm passes
over Galveston, the curved Texas-Louisiana shoreline from Bay City southwest
of Galveston over to the Mississippi River Delta would amplify the surge. The
continental shelf is wide in that region. Both of these factors together, Bush
said, "sets the stage for maximum storm surge."
More information
David Bush, PhD
Geologist, State University of West Georgia
Carrollton, GA 30118
770-836-4597
dbush@westga.edu
Robert S. Young, PhD
Geologist, Western Carolina University
Cullowhee, NC 27823
Tel: (828) 227-3822
Fax: (828) 227-7647
ryoung@wcu.edu
Martha J. Heil
American Institute of Physics
College Park, MD
301-209-3088
mheil@aip.org
|
