All due respect, they are quite a bit more than a thunderstorm and uncommon.
“While not the most intense or long-lived event ever observed, the June 29, 2012 Ohio Valley / Mid-Atlantic Derecho was noteworthy in producing the all-time highest recorded June or July wind gusts at several official observing sites along its path (Fort Wayne, Indiana, Zanesville, Ohio, and Huntington, West Virgina), in addition to widespread, significant wind damage. Five million people lost power from Chicago to the mid-Atlantic Coast, and 22 were killed. The storm also was notable for being arguably the first derecho to capture widespread media attention, striking as it did nearly every metropolitan area in a broadening path that extended from Chicago and Indianapolis to Baltimore, Washington, and Tidewater Virginia (Figures 1 and 2). “http://www.spc.noaa.gov/misc/AbtDerechos/casepages/jun292012page.htm
c’mon, don’t nit-pick. You know what I meant.