Busted pully!

I think this is a first, when i started my car last night i was letting it warm up in the driveway when i heard a loud crack. I quickly shut the car down and poped the hood and saw a snapped belt. Upon closer inspection i saw that the crank pully had a crack in it which had a spur of steel sticking out of it which i figure frayed the belt causing it to snap . Anyways i have za new set of pullys on the way, steeda adreed to replace them since i have only had them on for a few months. I did not notice any crack before they where installed but then again i didnt think to look. Im sure nobody has had this happen but if you did please chime in.