California has gone from extreme drought to extreme flooding.
The state has recently been battered by a cascade of atmospheric rivers -- long, narrow regions in the atmosphere that can carry moisture thousands of miles. Streets have turned into rivers while trees have been toppled, homes lost power, rivers swelled and major roadways were shuttered.
California is now extremely vulnerable to flooding because much of the state has been scarred by historic drought or devastating wildfires — meaning the land can't soak up much rainfall.
More than a dozen people have died in winter storms this year, according to the office of Gov. Gavin Newsom.

An abandoned car is trapped on a flooded street in San Diego on January 16.
Mike Blake/Reuters

Joey Klien salvages items from his house on January 16 after part of it was flooded in Carmel Valley.
Daniel Dreifuss.Reuters

Damage caused by recent storms is seen at the Capitola Pier on Sunday, January 15. The pier was built in 1857.
David McNew/AFP/Getty Images

Melissa Foley clears debris in her neighborhood as the San Lorenzo River rises in Felton on Saturday, January 14.
David Swanson/Reuters

A flooded field is seen in Salinas as the Salinas River begins to overflow its banks on Friday, January 13.
Justin Sullivan/Getty Images

National Guard troops, sheriff's office personnel and firefighters search for missing 5-year-old Kyle Doan near San Miguel on Thursday, January 12. Doan was pulled from his mother's hands by rushing floodwaters on January 9.
San Luis Obispo County Sheriff's Office/AP

Kelly Slate packs a mirror in the back of a truck after her home was flooded in Planada on Wednesday, January 11.
Justin Sullivan/Getty Images

A car drives through floodwaters in Planada on January 11.
Justin Sullivan/Getty Images

Residents in Piru work to push back wet mud that trapped cars and invaded some houses on January 11.
David McNew/Getty Images

A person walks near driftwood and storm debris that washed up in front of the Santa Cruz Beach Boardwalk amusement park.
Mario Tama/Getty Images

A San Diego firefighter rescues a dog from a flooded home in Merced on Tuesday, January 10.
Josh Edelson/AFP/Getty Images

Pauline Torres carries belongings from her flooded home in Merced on January 10.
Noah Berger/AP

A neighborhood is flooded in Merced.
Josh Edelson/AFP/Getty Images

Matt O'Brien shovels mud from a driveway on January 10 after the San Lorenzo River overflowed in Felton.
Nic Coury/AP

Several people had to be rescued after two vehicles fell into this sinkhole in Chatsworth on January 10.
David Swanson/Reuters

Commuters in downtown Los Angeles are shuttled over a flooded section of a pedestrian walkway leading to train platforms on the main level of Union Station.
Genaro Molina/Los Angeles Times/Getty Images

Cleanup takes place in Aptos on January 9 after streets and homes were flooded near the Rio Del Mar State Beach.
Melina Mara/The Washington Post via Getty Images

People arrive at an evacuation center in Santa Barbara on January 9.
Ringo H.W. Chiu/AP

A crew member is reflected in pools of water while setting up the red carpet for the Golden Globe Awards in Los Angeles.
Allen J. Schaben/Los Angeles Times via Getty Images

A home is flooded in Gilroy on January 9.
Josh Edelson/AFP/Getty Images

Colleen Kumada-McGowan stands in floodwaters in front of her home in Watsonville on January 9.
Brontë Wittpenn/San Francisco Chronicle via AP

Crews work to clear a mudslide on Highway 17 in Scotts Valley.
Carlos Avila Gonzalez/San Francisco Chronicle via AP

Naia Skogerson leaves her home in Aptos.
Nic Coury/AP

A road is damaged in Scotts Valley on January 9.
Neal Waters/Anadolu Agency via Getty Images

This aerial photo shows a tree that fell in Sacramento on January 8.
Fred Greaves/Reuters

Santa Cruz residents clear storm debris and stack sandbags near their homes on January 7.
Mike Kai Chen/The New York Times/Redux

Sandbages are piled in front of a door in Capitola on January 6.
Mike Kai Chen/The New York Times/Redux

Boone White leaps from his car after a large tree fell on it while he was driving near Capitola.
Shmuel Thaler/The Santa Cruz Sentinel via AP

A support piece from the Capitola Wharf is seen inside the storm-damaged restaurant Zelda's on the Beach.
Shmuel Thaler/The Santa Cruz Sentinel via AP

Evan Sousa, left, gets help from Calvin Drake as they push water out of his flooded apartment in Pacifica on January 5.
Karl Mondon/Bay Area News Group via AP

Henry Valletta cuts up a downed tree in Sacramento on January 5.
Max Whittaker/The New York Times/Redux

Residents walk in a damaged area of Aptos on January 5.
Carlos Barria/Reuters

Dominic King, owner of the restaurant My Thai Beach, surveys storm damage at his business in Capitola.
Nic Coury/AP

A vineyard is flooded in Walnut Grove on January 4.
Max Whittaker/The New York Times/Redux

Drivers in San Francisco barrel into standing water on Interstate 101 on January 4.
Josh Edelson/AFP/Getty Images

Khaled Dajani clears water from his flooded living room in San Francisco on December 31.
Mike Kai Chen/The New York Times/Redux