I've seen this happen before, just about once a year to someone I know. We get a lot of those strong flash storms around my home town. Let me be the first to say that trees are much bigger looking once they've fallen over. After every storm at my house, several branches would have fallen down, and we'd have to throw them in a field we had, for lack of anything to do with them. We were lucky not to have any trees growing close enough to our house for anything to hit them, though.