A combination of freak weather and decaying infrastructure could see dozens of cities in the Los Angeles area washed away by 20 feet of floodwater. Army engineers have pleaded with the federal government to avert a crisis.
Drought-stricken California seems an unlikely location for a flood of biblical proportions, but the US Geological Survey has repeatedly warned that a rare storm event, known as an “ARkStorm” could dump unprecedented amounts of rainfall onto the state, flooding the Central Valley, causing $300 billion in property damage and triggering the evacuation of millions of residents.
https://www.rt.com/usa/452117-mega-storm-california-dam/