Heat in Virginia, July 4 to 7, 1999

High pressure sat off the Mid-Atlantic coast from the 4th through the 7th, acting like a heat pump drawing extremely warm and humid air into Northern Virginia. Temperatures on the 4th through early on the 7th were oppressively hot, and extremely humid conditions added to the misery. These conditions continued until a cold front swept through the area during the afternoon of the 7th, ushering cooler and much less humid air. The mercury soared into the upper 90s to lower 100s during the period. Dew points were in the lower to middle 70s, creating heat indices between 100 and 115 degrees. Overnight lows only dipped into the 70s and heat index values ranged from the upper 70s to upper 80s. The heat index only dropped to 90 degrees at National Airport in the Washington D.C. suburbs on the morning of the 6th. Record highs were broken at Washington National Airport on the 5th and 6th. The record high at Dulles International Airport was broken on the 4th and tied on the 5th. High temperatures on the 3rd included 97 degrees at Winchester, 96 degrees at Woodstock, 95 degrees at Dale Enterprise, and 94 degrees at Sterling. Afternoon readings on the 4th included 103 degrees at Dale Enterprise, 102 degrees at Front Royal, 101 degrees at Woodstock, 100 degrees at Edinburg, 99 degrees at National Airport, 98 degrees at Fredericksburg and Luray, and 97 degrees at Dulles International Airport and Winchester. High temperatures on the 5th included 102 degrees at Washington National Airport, 101 degrees at Edinburg and Fredericksburg, 100 degrees at Orange, 99 degrees at Dulles International Airport and Staunton, and 98 degrees at Culpeper. Highs on the 6th included 103 degrees at Front Royal and National Airport, 102 degrees at Winchester, 101 degrees at Fredericksburg, 100 degrees at The Plains, and 99 degrees at Dulles Airport. Because of the 4th of July holiday weekend, many people were inconvenienced by the oppressive conditions. Many holiday events had low attendance, with the exception off the late evening fireworks displays which occurred after temperatures fell below 90 degrees. Those who spent considerable time outdoors where subject to heat related illnesses. On the early evening of the 3rd, a 58 year-old man who was hiking for two hours with his family near the Doyles River Trail at Shenandoah National Park in Rockingham County died from a heart attack brought on by heat stress. Rockingham officials reported 6 other heat related injuries from the 3rd through the 7th. The number of persons treated for heat related illnesses in other locations included at least 5 in Augusta County, 1 in Charlottesville, 9 in Fauquier County, 7 in Frederick and Loudoun Counties, 24 in Fairfax County, and 21 in Alexandria. In addition, 6,000 turkeys were killed by the heat wave in Orange County.Road surfaces and cars also fell victim to the heat. A major asphalt buckle occurred on Interstate 395 between King Street and Seminary Road in the Washington D.C. suburbs, closing all southbound lanes for a short time on the 8th. Tar on roads near Community Park and New Market in Shenandoah County melted and had to be covered with gravel. State police reported 30 vehicles were disabled by the heat. Virginia Power reported a record high consumption of energy during the late afternoon of the 5th and 6th. High demand for electrical power blew transformers, leading to widely scattered power outages. Staunton cancelled summer school classes on the 6th due to the heat. The heat also contributed to several wildfires. A fire in Rockingham County sparked by an electric fence burned 60 acres. One firefighter battling the blaze had to be treated for heat problems. In Shenandoah County, an overheated car off Virginia Route 720 ignited a fire that burned 9 acres of barley. The exhaust system of a second car caught fire and sparked another fire in the same field. Another 20 acres burned near Meems Bottom after a spark from farm machinery set a grass field ablaze. People setting off fireworks near Singers Mill set another blaze which burned a quarter acre of field grass and came within 100 yards of a home.