The cause of one of the year’s most memorable weather disasters is getting the boom this month — the spillway on the Lake Oroville Dam in California. In February, the spillway failed spectacularly, to the tune of 200,000 people evacuated from their homes. After torrential winter storms, water poured over the lake’s spillways. The main spillway, which was ostensibly designed to bear the weight, crumbled on one side and allowed a torrent to flow out of the spillway onto the wall of the dam itself. That’s problematic because this area of the dam is literally just a hill.