Stronger hurricanes spawn bigger storm surges
Pastor Dale Morgan
Stronger hurricanes spawn bigger storm surges*
Thursday, August 10, 2006 Posted: 1356 GMT (2156 HKT)
WASHINGTON (Reuters) -- Stronger hurricanes forecast for the next few
decades could flood major cities including Miami and New Orleans,
environmental scientists said Wednesday.
Storm surges -- walls of water up to 30 feet high pushed ashore by
hurricanes -- could pose a higher risk to coastal areas than the threat
of rising seas tied to global warming, scientists from the group
Environmental Defense said.
More intense hurricanes -- some as strong as 2005's devastating Katrina
-- are likely in the future, the scientists said, because global climate
change could mean warmer sea surface temperatures, which fuel
hurricanes' development.
"There's been a lot of talk about the threat to coastal areas of sea
level rise, and that is a very, very real issue ... but one that is
going to unfold over a period of decades, if not a century," said Bill
Chameides, Environmental Defense's chief scientist, in a telephone news
conference.
"What we think will actually be a more immediate risk to coastal areas
... is the threat of storm surge, which is actually exacerbated by sea
level rise due to these growing-intensity storms," Chameides said.
Using U.S. government data, the scientists created maps showing flood
risk areas in Wilmington, North Carolina; Charleston, South Carolina,
and Miami, based on projections of storm surges from hurricanes ranked
as Category Three, Category Four and Category Five.
Flood risk
A Category Three storm, with a typical surge of 9 feet to 12 feet above
normal, would pose a flood risk to all of Miami Beach and much of
downtown Miami, according to the scientists' projections.
By contrast, a Category Five storm, with surges of 18 feet or higher,
would pose a risk to a larger area, extending further inland, their maps
indicated.
For New Orleans, the scientists did not project possible risk of
flooding; instead, they used data from the U.S. Geological Survey
showing how far the flood waters went after devastating Hurricane
Katrina came ashore last year.
"As Hurricanes Katrina and Rita showed, the 9,546 square miles of land
close to sea level (in Louisiana) are especially vulnerable to storm
surges -- highly destructive moving crests of water that often cause the
bulk of the damage in a high-category storm," the scientists wrote online.
Chameides agrees with many climate scientists who believe human-caused
global warming is responsible for raising sea surface temperatures,
making stronger hurricanes more likely; but other scientists maintain
hurricane intensity goes in natural cycles, and say the record-breaking
2005 Atlantic and Caribbean season was part of a high-category hurricane
cycle.
U.S. government forecasters Tuesday revised their hurricane predictions
for 2006, saying the Atlantic hurricane season would be slightly less
intense than last year -- and less active than they predicted in May --
with 12 to 15 named storms and seven to nine hurricanes, of which three
or four could be classified as "major" hurricanes.
Last year there were 28 tropical storms, of which 15 became hurricanes,
including four major hurricanes, notably Katrina, which devastated New
Orleans, killed 1,300 people and caused $80 billion in damage.