The Indiana State Fair stage collapse was an incident during an August 13, 2011, outdoor concert by Sugarland as part of their Incredible Machine Tour at the Indiana State Fair in which a wind gust from an approaching severe thunderstorm hit the stage's temporary roof structure, causing it to collapse.

[2] At 8:00 p.m., Cindy Hoye, Executive Director for the Indiana State Fair Commission, held a meeting to discuss what effect the weather forecast would have on the 8:45 p.m. start time for the Sugarland show.

[2] At 8:39 p.m., the National Weather Service issued a severe thunderstorm warning indicating that hail with a diameter of 1 inch (25 mm) and winds over 60 miles per hour (97 km/h) were expected.

[citation needed] The Indiana State Fair Commission hired the engineering firm Thornton Tomasetti to lead the technical investigation into why the stage collapsed.

[4] In addition, the public safety and crisis management firm Witt Associates was hired to investigate the fair's preparedness and response to the incident.

James Lee Witt, the company's CEO, was the director of the Federal Emergency Management Agency (FEMA) for the Clinton Administration.

[5] According to the final incident report released by Thornton Tomasetti: The failure ... was due to the inadequate capacity of the lateral load resisting system, which was comprised of guy lines connected to concrete "Jersey barrier" ballast.

[6]The concrete barriers used as anchors for the guy lines were not fixed in place; they resisted loading only by friction with the ground and through their own weight—about 4,200 pounds (1,900 kg).

[6] Just before the collapse, wind loading caused several of the barriers to slide or pivot from their original positions, allowing the top of the truss structure to lean toward the crowd.

[6] The report also pointed out a number of procedural factors that either contributed to the structural problems or prevented them from being discovered:[6] Several issues were found with the level of preparedness and the actions of State Fair officials and Sugarland representatives on the evening of the incident that contributed to the number of casualties:[2] Several lawsuits were filed after the event.