Why Are These Vans Levitating?

It's not everyday you see a few vans just start floating and flip over!

Well that is exactly what happened, kind of. I guess they were working on the power lines and the street sweeper caught a dead power line on the ground. Well those things must be pretty powerful because it picked up 2 vans the the car next to it!

You can't see the power line, so it looks like something out of a comic book movie!