Randy Mann: Unusual windstorm hits East with wallop

At the end of June, millions of people from Ohio eastward through the Mid-Atlantic states were without power for more than 10 days.

A violent windstorm usually associated with a strong band of thunderstorms that is accompanied by torrential downpours, large hailstones and even deadly tornadoes swept through that part of the country.

This type of weather event is called a derecho, according to the National Oceanic and Atmospheric Administration.

The term “straight-line wind damage” is given to the disastrous consequences of a derecho like the one that hit the eastern U.S. last month.

Unlike a hurricane, which can be tracked for days or even weeks before its impact, the recent derecho gave no warnings of its arrival. By definition, if the wind damage extends for more than 240 miles and includes gusts of at least 58 mph or more, then the event may be classified as a derecho.

My sister, Susan Ayers, who lives in Maryland, was affected by the derecho that moved into the Mid-Atlantic region at the end of June.

She told me what happened at that time. “We were five days without power, which means, in addition to no electricity, and no air conditioning in 97 degree-plus heat, that those of us with wells and septic tanks had no water. Therefore, no showers! Smelly!

“The power generated by our portable generator was used for keeping the refrigerator and freezer going, and plugging in and out small appliances, such as a microwave, a coffee pot and a couple of hairdryers.

“After five full days, I gave up and went to our marina for a shower. Then we went boating, and (my husband) Mark washed in the bay, with a bar of soap.”

Derechos in the U.S. are most common from May through August. East of the Rockies, a derecho hits approximately every three or four years. West of the Continental Divide, derechos are rare, occurring less than once a decade.

The term derecho was coined in 1888 by Gustavus Hinrichs, a physics professor at the University of Iowa. Hinrichs decided to use the word derecho to define various nontornadic events. In Spanish, derecho means “direct or straight ahead.” The definition was published later in 1888 in the American Meteorological Journal.