Filled my weber chimney starter with royal oak lump charcoal, like I always do. Put 2 sheets of crumpled newspaper in the bottom and lit it with a stick lighter, like I always do. Set it on the concrete driveway and waited for the coals to grey over, like I always do. But this time for some reason after about 15 minutes it made a loud bang, knocked the chimney over, and blew a 8" diameter 1/2" deep hole in the concrete. Seriously, WTF?