Drought in Virginia, June 1 to 30, 1999

High pressure was the dominant weather feature across Northern Virginia during the month. This weather pattern directed rain producing low pressure systems north of the region and continued the climatological drought that has gripped the area since last summer. By the last week of June, the Palmer Drought Index, a measure of long term drought conditions, indicated Northern Virginia was in a severe drought. June was the 8th month in the past 12 months that precipitation was below normal. From July 1998 through June 1999 precipitation was a staggering 15 inches below average, the 3rd driest 12 months on record. Only 3.00 inches of rain fell at Dulles International Airport during the month of June, 0.92 inches below normal. Reagan National Airport in Arlington reported a monthly total of 2.26 inches, 1.12 inches below normal. Measurable rain only fell on 8 days during the month, with 1.32 inches of the total falling on the 14th. Additional June rainfall totals included Frederick County at 2.2 inches, Shenandoah and Madison County at 1.0 inches, Warren County at 1.4 inches, Rockingham at 0.7 inches, Page County at 1.6 inches, Clark County at 1.9 inches, Orange and Nelson County at 0.8 inches, Augusta and Fauquier County at 1.3 inches, Highland County at only 0.4 inches, Culpeper County at 1.6 inches, Rappahannock County at 1.1 inches, Loudoun County at 2.3 inches, and Fairfax County at 2.5 inches. The lack of rainfall affected water levels along the Potomac River, the main water source for extreme Northern Virginia. The flow of water past Washington D.C. hovered around 18% of average, and many new record low daily flows were recorded in upstream tributaries of the river. Unusually high proportions of river flow, 33%, were diverted out of the Potomac River into public water supplies during the month. The normal diversion rate is about 5%. Monthly flow rates of the Potomac River have been below average for the last 10 months. Flows in the Potomac, Shenandoah, and Rappahannock basins, were equal to or slightly below minimum June daily mean flow values recorded during the 1980-82 drought. Many gaging stations reported streamflow at or below the 90 percent exceedence, and a few reported streamflow values at or below the 95th percentile. New daily low flows were set on the North Fork of the Shenandoah at both Cootes Store and Strasburg. Streamflow of the Rappahannock River at Fredericksburg was only 14% of normal. Streamflow of the Rapidan River at Culpeper was only 20% of normal. Fish kills were reported on the North Fork and main Stem of the Shenandoah River from the buildup of algae and low water levels. The volume of water entering the Occoquan Reservoir was the smallest since record keeping began 71 years ago. With such low water tables, the cities of Fredericksburg, Waynesboro, Winchester, and Berryville, and Frederick and Shenandoah Counties were forced to start voluntary water restrictions. The community of Round Hill in Loudoun County instituted mandatory water restrictions because their reservoir dipped below half of its 200,000 gallon capacity. Warren County considered seeking federal assistance through a drought emergency. The community of High Knob was without water by the 17th. The Ni River Reservoir, main water source for Spotsylvania County, dipped 16 inches below full by mid month. Beaverdam Reservoir in Loudoun County was half full, still recovering from being drained to keep the Goose Creek Reservoir full. The lack of precipitation also continued to beat down crops and pastureland. Watering holes and irrigation sources continued to dry up, forcing many farmers to carry water to livestock. 68% of pasture land and 63% of hay across the state was reported in poor or very poor condition. Hay producers reported less than half of their normal yields from their second cutting. 78% of topsoil was reported as short or very short of moisture by the end of the month. Some farmers had to reduce their herd sizes in order to stretch hay and water supplies. Corn crops were cut by 25% and were 12 to 14 inches shorter than normal. The alfalfa crop was cut by 30%. Soil evaporation loss per day averaged around 0.3 inches. In addition to agricultural lands, forest and rural vegetation was also dangerously dry. Many small fires were reported, starting from causes as unusual as a car backfiring or an overheated tractor.