When you think of California’s climate, you probably think most often of the multi-year droughts that have affected the region over time. But we also know that the area can experience devastating floods, as witnessed by the damage to the Oroville Dam there by floodwater a few years ago. Many of these floods are caused by events called “atmospheric rivers”, which bring streams of very humid air to the region, supercharging the atmosphere and creating the perfect conditions for massive rain events.
Paleoclimatologists have used sediments to determine that these huge rain events come about once a century, and have the potential to flood the Central Valley, center of western agriculture and the source of a lot of the vegetables, dairy, and nuts that we eat in the US. The last massive event was the Great Flood of 1861-62, which caused tremendous damage. This article from Mother Jones, which was republished in Wired magazine, provides some historical context about the storms and how it might affect California agriculture in the future.