x-rays as far as 70 miles, heaved gurneys for blocks and. windows are blown out. debris hanging outside of the windows. part of the roof the top is missing. i mean, i m standing behind the hospital and cinder block walls, brick walls, are just crumbled. reporter: the tornado also struck joplin high school, just as seniors were finishing graduation ceremonies nearby. parents and students escaped but the school was demolished. i walked around as much as i could to see it. it looked like it s been bombed from the outside-in. i mean, it s terrible. reporter: the storm left cars and trucks on top of each other. this walmart, now flattened, this home depot crushed. we don t know how many shoppers were inside the store. thankfully residents. by our count we had 17 minutes time from the sirens and first report of a strike. reporter: more than 4 hours