The one technical solution that I have heard that seems feasible is an inflatable cover, sort of a flat zeppelin on top. I don't know how they would position it, and how long it would take to move it on top. But imagine Goodyear or Michelin or some tire company doing the engineering. That would be a good PR. Make it transparent and you have an even more unique "thing" on top. (The thought just popped in my mind that the sponsor and developer of this thing should be Trojan/Durex. Possible slogan: "We are there whenever things get wet") Sorry. Been too long in the wild by now.