Hank Silverberg, wtop.com
WASHINGTON - One of the most devastating storms in U.S. history came slowly up the east coast in late June 1972 and hit the Mid-Atlantic region hard, dropping 14 inches of rain from June 20 to June 23.
Rivers and creeks dramatically overflowed their banks. Portions of I-95 were flooded with water. The lower part of the National Zoo was inundated by Rock Creek. The Potomac breached its banks and saturated lower Georgetown. Main Street in Laurel was under the water of the Patuxent River.
Before the water receded, 34 people had died in Virginia, Maryland and D.C. Many of them were trapped in cars by raging flood waters.
ABC7 Chief Meteorologist Doug Hill, who was stationed at Andrews Air Force base in Prince Georges County at the time, says Agnes was actually downgraded to a tropical strom by the time it hit the region. High water did most of the damage.
"There was a shopping center in Arlandria, and the firefighters just had to helplessly watch the fires rage because there was no way to get to it.The water was blocking them from getting in," he said.
More than one hundred homes were destroyed by the flooding, and damage was estimated at $3.1 billion dollars in six states, with Pennsylvania taking the biggest hit.
After the storm, many water level gages were installed in rivers and streams to help monitor flooding and other flood control measures were taken. The flood gates in lower Georgetown along the Potomac were finished in 1986.
Hill says the area is still very susceptible to damage from hurricanes and other coastal storms. But he says computer models have made forecasting storms more accurate.
"Not only can we visualize on computer screens how bad the flooding will be, we can also visualize where that flooding will be as well."
That makes it easier to issue warnings and get people prepared.
(Copyright 2012 by WTOP. All Rights Reserved.)
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