Brett F. Sanders, a professor of civil and environmental engineering at UC Irvine, studies flooding and erosion hazards. “Sea caves are always at risk of flash flooding from strong waves,” he says. “A big storm event can trigger an instability of the rock surrounding the cave, leading to a partial or even complete collapse of the cave.” Further, “with a big winter storm, the waves can be much bigger, which heightens the strength of currents in and out of the caves,” he says.