Phoenix, Arizona, isn’t a place that’s known for rainy weather, so it’s probably no surprise that when it rains in Phoenix, weird things happen.

Earlier this month, an unusually large storm flooded streets all across the city, but that’s not even the strangest part. The oddest thing about it was a pressure differential that built up between the sewers and the streets, which was caused by the flooding water. This managed to increase air pressure beneath the streets to the point where a 150-pound manhole cover appeared to be levitating.