{"id":1257,"date":"2013-06-13T13:40:51","date_gmt":"2013-06-13T13:40:51","guid":{"rendered":"http:\/\/ialert.com\/blog\/?p=1257"},"modified":"2026-06-11T23:11:03","modified_gmt":"2026-06-11T23:11:03","slug":"what-is-a-derecho","status":"publish","type":"post","link":"https:\/\/ialert.com\/blog\/weather-articles\/what-is-a-derecho\/","title":{"rendered":"What is a Derecho?"},"content":{"rendered":"

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\"Radar
Radar composite of the June 29, 2012 derecho, Midwest to Mid-Atlantic<\/figcaption><\/figure>\n

A derecho<\/strong> (deh-REY-cho) is a widespread, long-lived windstorm produced by a fast-moving line or cluster of severe thunderstorms. Derechos typically race east or
\nsoutheast and generate a damaging straight-line wind field along the entire length of the storm, with damage swaths that can stretch for hundreds of miles. The term comes from the
\nSpanish word for “straight,” a nod to the straight-line nature of the wind damage, in contrast to the rotational damage of a tornado. The Storm Prediction Center’s derecho facts page<\/a> maintains the official definition and
\nclimatology.<\/p>\n

On radar<\/a>, a derecho often displays the signature “bow echo,” a bent, reverse-C curve in the line of storms caused by intense
\nrain-cooled air surging out ahead of the system.<\/p>\n

The June 2012 Derecho: Chicago to Washington DC<\/h2>\n

The June 29, 2012 radar imagery composite below shows an actual derecho that started near Chicago and pushed into Washington DC in about 12 hours. Notice the largest width of the
\nstorm is over 240 miles, the storm path in the image covers nearly 450 miles (the full path extended 700 miles into DC), and the signature bow echo is clearly visible.<\/p>\n

That storm killed 22 people and left more than 4 million customers without power across 10 states, with many outages lasting a week during a record heat wave.<\/p>\n

Official Derecho Criteria<\/h2>\n
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