A <a href="https://en.wikipedia.org/wiki/Derecho" id="mwAUE" rel="mw:WikiLink" title="Derecho">derecho</a> <a href="https://en.wikipedia.org/wiki/June_2012_North_American_derecho" id="mwAUI" rel="mw:WikiLink" title="June 2012 North American derecho">sweeps</a> across the eastern United States, leaving at least 22 people dead and millions without power.