Chincoteague, Virginia, including the Pamlico and Albemarle Sounds and the lower Chesapeake Bay. The NHC also issued a tropical storm watch south of Little River, South Carolina to the mouth of the Santee River, as well as from Chincoteague, Virginia northward to Little Egg Inlet, New Jersey. Hurricane and tropical storm warnings were gradually issued for portions of the East Coast of the United States. By the time Isabel made landfall, a tropical storm warning existed from Chincoteague, Virginia to Fire Island, New York and from Cape Fear, North Carolina to the mouth of the Santee River in South Carolina, and a hurricane warning existed from Chincoteague, Virginia to Cape Fear. Landfall forecasts were very accurate; from three days prior, the average track forecast error for its landfall was only 36 miles (58 km), and for 48 hours in advance the average track error was 18 miles (29 km). Officials declared mandatory evacuations for 24 counties in North Carolina, Virginia, and Maryland, though in general not many left. According to a survey conducted by the United States Department of Commerce, evacuation rates were estimated as follows; 45% in the Outer Banks, 23% in the area around the Pamlico Sound, 23% in Virginia, and about 15% in Maryland. The threat of Isabel resulted in the evacuation of hundreds of thousands of residents, primarily in North Carolina and Virginia, and included more than 12,000 residents staying in emergency shelters. 19 major airports along the East Coast of the United States were closed, with more than 1,500 flights canceled. The Washington Metro and Metrobus system closed prior to the arrival of the storm, and Amtrak canceled nearly all trains south of the nation's capital. Schools and businesses throughout its path closed prior to Isabel's arrival to allow time to prepare; hardware and home improvement stores reported brisk business of plywood, flashlights, batteries, and portable generators, as residents prepared for the storm's potential impact. The federal government was closed excluding emergency staff members. The United States Navy ordered the removal of 40 ships and submarines and dozens of aircraft from naval sites near Norfolk, Virginia. A contingency plan was established at the Tomb of the Unknowns at Arlington National Cemetery that, should the winds exceed 120 mph (190 km/h), the guards could take positions in the trophy room (above the Tomb Plaza and providing continual sight of the Tomb) but the plan was never