Colvin Run in Lake Fairfax Park in Reston, Va., is seen Tuesday. It is normally flush with water. Jahi Chikwendiu/The Washington Post

More than a dozen states from the Ohio Valley and northern Mid-Atlantic to the South are under some level of drought, according to federal forecasters. In some areas, the drought is so severe that a state of emergency and other alerts are in effect.

A “flash” drought – described such because of its rapid onset – developed over large parts of the eastern United States during June and persisted through July. In early June, only South Florida was experiencing drought, but it has since expanded to cover a zone from Ohio to Georgia and several surrounding states.

The combination of record-challenging heat, a lack of rain and intense sunshine fueled this flash drought.

In recent weeks, parts of North Carolina, Georgia and Tennessee have seen more regular rainfall, easing the drought. Still, rain remained spotty overall in July, which is typically one of the wettest months of the year, so a lot more precipitation is needed for a larger area to see significant improvement.

WHERE ARE DROUGHT CONDITIONS THE WORST?

The most intense drought covers the area from eastern West Virginia, northwest Virginia and parts of western Maryland into south-central Pennsylvania.

The region has seen relatively little rain in recent weeks, and much of it is under a Level 4 out of 5 “extreme” drought, which expanded somewhat over the past week to include portions of southern Pennsylvania.

Part of eastern South Carolina is also in extreme drought; the rest of the state is in a Level 3 out of 5 “severe” drought.

WHAT ARE THE RAINFALL DEFICITS IN AFFECTED AREAS?

Many places in the eastern United States, even those not considered in a drought, have recorded rainfall deficits this summer, from the Ohio Valley to New England and southward. Welcome rain in July brought several areas out of the drought, but many locations have significant rainfall deficits since June 1, including:

• Mansfield, Ohio (southwest of Cleveland) – 2.77 inches have fallen since June 1, which is 5.88 inches below normal.

• Elkins, W.Va. – 5.21 inches have fallen, which is 5.26 inches below normal.

• Baltimore – 2.81 inches have fallen, which is 5.65 inches below normal.

• Charlottesville – 2.78 inches have fallen, which is 4.97 inches below normal.

WHAT ARE SOME OF THE EFFECTS SEEN IN DROUGHT-STRICKEN AREAS?

West Virginia was placed under a state of emergency late last week by Gov. Jim Justice. A drought watch was also announced for the D.C. area and other parts of Maryland.

Additionally, the U.S. Department of Agriculture designated 15 counties in the Shenandoah Valley region and western D.C. suburbs as primary disaster areas eligible for emergency relief loans.

Farmers in the border regions of Virginia, West Virginia and Maryland have been particularly hard hit. The owner of Higson’s Farm in Wiley Ford, W.Va., told local media that it’s “probably one of the driest years I’ve seen.”

Farther south, conditions have improved in much of North Carolina after a record-dry June, but less so in South Carolina, where drought remains particularly intense. The U.S. Small Business Administration announced Wednesday that disaster loans will be available to various sectors affected by drought there.

WHY HAVE DROUGHT CONDITIONS DEVELOPED? 

June was historically dry in much of the Mid-Atlantic and into parts of the Southeast and Ohio Valley. In parts of Virginia, almost no rain fell as a sun-baked heat dome sprawled over the region.

Cities that observed a top five driest June include Cincinnati (second-driest); Martinsburg, W.Va. (driest); Washington (fourth-driest); Greensboro, N.C. (fourth-driest); Myrtle Beach, S.C. (second-driest); and Macon, Ga. (third-driest). Many spots from Ohio into the Mid-Atlantic stayed dry through July.

West Virginia overall has a precipitation deficit average of about 4.5 inches below average for the summer to date.

WHEN WILL DROUGHT RELIEF ARRIVE?

In a number of locations, some relief has already arrived, especially in the Southeast and for areas east of Interstate 95 through the Mid-Atlantic. The National Weather Service outlook for August has better odds than usual of above-average rainfall in much of the eastern United States.

August’s drought outlook (shown above) from the Weather Service suggests it will probably end around the periphery of the drought area and improve elsewhere. This will become increasingly important as the region heads into late summer and fall when wildfire risks increase.