The risk of megafloods is increasing dramatically as global temperatures rise and store more moisture in the atmosphere. We are not as prepared as many assume. For California, both history and modeling studies of the storm events we can expect in the future provide interesting insights.
Flooding that filled the Central Valley region of California to the point of becoming an inland sea, with water lapping from the Coast Ranges to the Sierra Nevada foothills, was part of Native American oral traditions. And that is exactly what happened in the Great Flood of 1862. If a similar major flood occurs, there will be catastrophic consequences.