. >> reporter: cindy hoye, the fair's director, was backstage on her way to call off the concert because of approaching storms, when that sudden, powerful gust smacked the stage. [ screaming ] >> oh, my god! >> reporter: that night, fair officials spoke at least five times with national weather service forecasters. but violent wind gusts, something they called "gustnadoeoe" swept up from the ground. strong gusts of wind that swirl like a tornado in advance of a storm front too quickly to be detected. that is what apparently happened here. the wind gusts here were so isolated they never hit this part of the park, where kids riding the ferris wheel were unscathed, only a few hundred feet away from the concert stage. but 15 miles away, at another outdoor concert, officials did order a mandatory evacuation just 30 minutes before the state fair tragedy. the wind gusts moved so quickly here it was impossible for some to escape. but experts say with severe weather in the air, it's smart to have a plan and know a safe structure where you can take shelter. diane. >> all right, chris, thank you fo