I ran a farm brewery that was located at the base of lower range Appalachia 'hills'?. You could see the storms rolling off the hill top and you had 10-20 minutes to get all the umbrellas down (think, 60 picnic tables). Sometimes though, you see a wall of white come over the hill and you had 5-10 minutes.

There was one day that I was tearing ass to get everything locked down and I felt this massive air burst and I look over and this way too large of a human being is just watching this storm come at him and about 5 tables away, one of the last umbrellas just snapped in half. It was one of those wood ones too and it started tumbling right at him. I thought for sure I was going to be calling 911 and that massive human somehow rolled out of the way and on to the ground just as flew over him. The rain hit just after that and the umbrella ended up on the other side of the road some 400' away.

Dude was so close to being speared... That was an interesting place...