The July 2011 Iowa-Illinois-Michigan-Ohio Derecho was a derecho event that happened on July 11, 2011 in the states of Iowa, Illinois, Michigan, and Ohio. On the morning of July 11, 2011, a powerful long-lasting straight-line windstorm, known as a derecho, developed over central Iowa and carved a path of extensive damage across east central Iowa. The storm first took shape as a cluster of low end severe storms over southern Nebraska during the late afternoon of July 10. The system continued northeastward and entered western Iowa at 1:00am, still only as a marginal line of severe storms. As the system passed through the northern Des Moines metro area at 3:30am, it interacted with an outflow boundary from the storms to the north and rapidly intensified as it accelerated eastward. Over the nex