The reservoir exceeded its capacity over the weekend, which sent water overflowing into an unlined, emergency spillway. That overflow sent soil, rock and forest debris into the Feather River below. Meanwhile, the Herculean effort to reinforce the emergency spillway before more rain arrived used a caravan of helicopters and trucks to fill three deep fissures in the dirt hillside with rocks and cement. As long as the lake doesn’t reach capacity the emergency spillway won’t be used, Croyle said. The incoming storm system is weaker than the one that overwhelmed the lake last week after the dam’s main spillway eroded to the point of fracture, Croyle said.

Source: Los Angeles Times February 16, 2017 21:41 UTC