Why does high wind cause power cuts?

May sound like a stupid question but then "there's no such thing as...". Is it typically because the phases in a three phase line touch? Or because branches blow into the lines and arc across? Or sometimes one thing, sometimes another?


Google let me down, so posting this - in one of those brief intervals when we do have power today :) It's the fact that what ever is causing them is obviously easily resettable - by the rate ours has been going on and off today - that made me start thinking about it. (It's on the HV lines affecting my village and half the adjacent small town. But not, you'll all be relieved to hear, the Ginsters' pasty factory which is on the other side of town :D ) 


Thanks,


Andy