Imagine a rainstorm so large that it would be like hurricane Katrina hitting every day for a month.
Countless homes would be destroyed as if a million tornadoes roared through the city, and the cost of cleaning up would plunge the entire world into an economic depression for decades.
It sounds like a scary script from a disaster movie right? But scientists say this is no fantasy. It will happen, and will destroy much of California.
Tthey're predicting a superstorm that would turn a flood control channel into a river the size of the Mississippi, and would literally wash away many buildings.
Metrorologist Evelyn Taft from KCAL in Los Angeles says the storm will dump more than ten feet of water.
"We could possibly see a third of the state under water in a storm like this," says Taft.
They're calling it the "ark storm" like the biblical storm that forced Noah and his animals into the ark.
It would leave more people homeless than the Haiti earthquake. A mini version of the superstorm is happening right now in Brisbane, Australia.
Dr. Lucy Jones from the U.S. Geological Survey created a computer model of the storm. She says the ark storm would be the most expensive natural disaster in history, saying, "We estimate it could cost as much as a trillion dollars."
When will it happen? No one can predict with certainty, but one thing is for sure—when it comes, it will leave behind devastation and destruction like we've never seen before.