Tropical Storm Chantal has been downgraded to a tropical depression but is raising concerns of flash flooding in central North Carolina and south-central Virginia.

Dozens of residents needed to be rescued from rising water, and hundreds of roads were closed as the storm moved over the central part of North Carolina.

Tropical Storm Chantal might have had the perfect recipe for catching people unawares: It formed rapidly (only reaching tropical storm status on Saturday) over a holiday weekend and moved slowly while dropping torrential rain.