Yesterday I posted a picture of my house losing its roof, and yesterday I got like 20 calls for repairs to other peoples roofs. Here is one of the worst ones. 
It is a reminder, that no matter how well you build stuff, nature is still the boss on some level. This roof also had some signs of needing repairs, but when neglected stuff like this can happen. So check up on your roofs, most people forget about them until it is too late, but sometimes there is nothing you can do. 