alex perez is in iowa tonight. >> reporter: tonight, terrifying video showing the moment the monster tornado ripped through iowa. the national weather service believes it was an ef-3 tornado. winds of at least 136 miles per hour. destroying parts of the town, just outside of des moines. >> this is the worst that anyone has seen in quite a long time. >> reporter: severe storms hitting other parts of iowa. baseball-sized hail raining down, cracking windshields. at least seven people killed in storms across iowa, including two young members of the same family, just 5 and 2 years old. this drone footage capturing the devastation. roofs torn off. buildings reduced to rubble. more than 50 homes damaged or destroyed. >> we were hunkered down in the basement. and it was the scariest thing i've ever experienced. >> reporter: jennifer and adam o'neil, owners of a flower farm, showing the devastation. >> our red barn is gone. we're standing on the foundation