Rainwater that Hurricane Isabel dumped in regional mountains caused the Potomac River yesterday to sweep over its banks near Point of Rocks, Md., and Shenandoah, Va.
Officials with the National Weather Service said flooding will occur along the entire route of the river as the excess water makes its way from the mountains of Maryland, Virginia, West Virginia and Pennsylvania to the Chesapeake Bay.
The crest was expected to reach Little Falls, just outside the District, by this afternoon, causing minor flooding, the weather service said. Minor flooding also was predicted in the tidal Potomac at Wisconsin Avenue during high tide today.
“Currently, soils are quite wet and streams in the mid-Atlantic area are running higher than normal,” said a weather service spokeswoman. “With rivers already at high levels, heavy rain could cause significant river flooding.”
Isabel dumped up to 13 inches of rain northwest of the District after it tore through North Carolina, Virginia, Maryland and the D.C. area on Friday.
National Park Service officials yesterday closed all 184.5 miles of the Chesapeake & Ohio Canal National Historical Park because of expected flooding. The park will remain closed until individual areas of the park are determined safe, said acting park superintendent Kevin Brandt.
“The storm is over, and the weather may be pleasant, but hazardous conditions may still exist,” Mr. Brandt said. The combined runoff from upstream tributaries can cause the Potomac River to rise quickly and create dangerous flooding.”
Since June, above-normal rainfall has been recorded from Columbia, S.C., which recorded a 20 percent increase, to the Scranton-Wilkes Barre area of northeastern Pennsylvania, which has had a 100 percent increase.
Moderate flooding occurred yesterday morning at Paw Paw, W.Va., where the Potomac reached 33 feet, 8 feet above flood stage, by noon. At about the same time near Point of Rocks, the river had swelled to 18.6 feet, 2 feet above flood stage, and was expected to reach its maximum depth of 24.5 feet by 8 p.m.
The 24-foot mark is barely half the record crest for the river which is 41 feet, which it achieved in 1936. At 24 feet, the river is expected to flood boat houses and docks, but it is not high enough to damage any homes in the area.
The Weather Service said the public cannot afford to overlook the danger of flooding while focusing on the storm surge’s devouring coastal areas, trees and telephone poles toppled by winds.
“What most people don’t realize is that over the last 30 years, more than half of all hurricane fatalities are due to inland flooding,” said Susan Weaver of the weather service.
• This article is based in part on wire service reports.
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