I'd go with the Prius. You say the Jeep is larger and heavier, better in adverse weather. I don't think the Prius is going to be blown over by any winds. And if winds are so strong that it could blow the Prius over, I don't think you should be driving anyways. Besides, the size and mass of the Jeep might even end up pinning you under it when you thought it was a good thing.