Storm surges seen rising

BALTIMORE (AP) — New computer simulations by government scientists show that hurricane storm surges in the Chesapeake Bay could get dramatically worse than those caused by Tropical Storm Isabel in 2003.

The researchers found that under some conditions a Category 4 hurricane landing in the Carolinas could produce storm surges as high as 18 or 20 feet in Baltimore at high tide. That is at least 10 feet above Isabel’s high-water mark.

The government used the latest version of its computerized SLOSH model to predict the surge. The name is an acronym for Sea, Lake and Overland Surges from Hurricanes, produced by the National Weather Service and the National Hurricane Center.

The projections show 18-foot storm surges are possible along the shoreline of Baltimore County, where Isabel did the most damage. Parts of Harford and Anne Arundel counties are just as vulnerable.

“I guess I’m a little surprised the values are as high as they are,” said Wilson Shaffer, chief of the Weather Service’s evaluation branch in Silver Spring and a leader of the project.

Mr. Shaffer said the precise combinations of tide, storm strength, track, size and forward speed needed to generate an 18-foot storm surge on the Bay are rare but “within the realm of possibility.”

Emergency managers, eager to avoid being unprepared for a catastrophe on the scale of Hurricane Katrina, are taking note of the predictions, the Baltimore Sun reported.

“A 20-some-foot storm surge up the Bay is not something we want to take lightly,” said Robert Ward of the Maryland Emergency Management Agency.

The agency is working with the U.S. Army Corps of Engineers and area officials to turn the simulation data into updated maps for emergency planning. The new maps will show how much farther inland flooding could stretch under the proper conditions.

Mr. Shaffer is scheduled to present his findings to state emergency managers and demonstrate the SLOSH model software Thursday.

Lt. Mark Demski of Baltimore County’s Fire Department and its office of Homeland Security Management acknowledged that emergency managers failed to predict the extent of surging with Isabel, which made landfall as a Category 2 storm.

“We are involving a lot more people in this SLOSH training … so we can be better prepared for these situations,” he said.

Mr. Shaffer said the SLOSH simulation study was expanded because the previous model, in 2000, did not indicate the extent of the storm surge during Isabel.

The worst outcomes emerged from scenarios in which storms made landfall in the Carolinas at Category 4 and produced a storm surge arriving with high tide in the Chesapeake.

The resulting map shows the worst flooding that could be expected and where it would occur under such conditions.

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