Last year, a derecho caused at least $1 billion in damage from Chicago to Washington, killing 13 people and leaving more than 4 million people without power, according to the weather service. Winds reached nearly 100 mph in some places and in addition to the 13 people who died from downed trees, another 34 people died from the heat wave that followed in areas without power.
Derechoes, with winds of at least 58 mph, occur about once a year in the Midwest. Rarer than tornadoes but with weaker winds, derechoes produce damage over a much wider area.
Wednesday’s storm probably won’t be as powerful as 2012’s historic one, but it is expected to cause widespread problems, Bunting said.
The storms are the type that will move so fast that “by the time you see the dark sky and distant thunder you may have only minutes to get to safe shelter,” Bunting said.
The storms will start late morning or early afternoon in eastern Iowa, hit Chicago by early afternoon and move east at about 40 mph, Bunting said. If the storm remains intact after crossing the Appalachian Mountains, which would be rare for a derecho, it should hit the Washington area by late afternoon or early evening, he said.
For Washington, Philadelphia and parts of the Mid-Atlantic the big storm risk continues and even increases a bit Thursday, according to the weather service.