What kind of bathroom exhaust vent should I use in a high wind area?

I have the standard louvre exhast vents that go from my bathroom fans to the outside of my house. I live in a high wind area and they are constantly flapping in the breeze, letting in cold air and they are very loud. Is there any product out there (for vinyl siding) that won't flap in the breeze but will open when the fan is on?|||Vent system? that when the system is engaged the louvres open and the fan motor turns on! check into the inline , booster fan for furnace duct work, most home bigboxes-warehouses will have them in the plumbing dept. if not try Graingers.