9 people killed in California’s massive storm.

State officials have reported that nine people across California died in the biggest storm of the season, a major atmospheric river that left a trail of destruction due to dangerous winds and historic rains.

Among the deaths, four were killed by fallen trees in Northern California and two died in car wrecks in Southern California, officials said.

The storm initially whipped into Northern California on Saturday as a bomb cyclone — meaning it rapidly intensified — fueling dangerous winds on top of an already moisture-heavy system. Wind gusts along the Northern and Central California coast exceeded 90 and 100 mph in some areas, as the storm unleashed the beginning of a deluge of rain.

By Sunday and Monday, the system was walloping Southern California, dumping record-breaking rainfall, causing hundreds of mudslides and debris flows and forcing evacuations and water rescues.

The storm — fueled by El Niño, human-caused climate change and typical winter weather patterns — resulted in widespread power outages, road closures and flooding.

Here’s what The Times has been able to confirm about the nine people who died in the storm, in the order they occurred:

Feb. 1 in San Mateo County

A man in San Mateo County died Thursday after his vehicle hydroplaned and struck a tree, becoming the first storm-related death, according to Brian Ferguson, a spokesperson for the governor’s Office of Emergency Services. It wasn’t immediately clear if the heavy rain in the area at the time of the accident was brought on by the storm that hit the Northern California coast two days later.

Feb. 3 in Sacramento County

A woman in Sacramento County was killed by a fallen tree in her backyard, Ferguson said. Additional details were not immediately available from the Sacramento County Sheriff’s Office.

Feb. 4 in Sutter, Sacramento, and Santa Cruz counties

Three men were killed by downed trees in Northern California the next day.

Chad Ensey, 41, of Carmichael suffered blunt-force trauma and died at a hospital after a tree fell on him in his backyard amid strong wind, according to the Sacramento County Sheriff’s Office.

In the rural Santa Cruz County community of Boulder Creek, Robert Brainard III, 45, was killed when a tree fell on his home, officials there said.

And in Sutter County, 82-year-old David Gomes was found dead beneath a fallen redwood tree in his backyard, authorities said.

Feb. 5 in San Bernardino County

In San Bernardino County, a 69-year-old man died after losing control of his truck in Yucaipa, sending it into an embankment that submerged part of the vehicle, according to the California Highway Patrol. The San Bernardino man was taken to a hospital, where he died of his injuries. His identity wasn’t immediately available.

Ferguson also confirmed another traffic death in Southern California on this day, but the details weren’t immediately clear.

Feb. 5 in San Luis Obispo County

A 90-year-old woman in Los Osos died after the power went out at her home, where she was in hospice care and dependent on oxygen, according to San Luis Obispo County Sheriff’s spokesperson Tony Cipolla.

She called 911 after losing power and medics responded, but she died soon after, Cipolla said. He did not immediately provide her name.

Feb. 6 in San Diego County

A person was found dead in the Tijuana River along the Mexico border, according to Mónica Muñoz, a spokesperson for the San Diego Fire Department.

Firefighters were called to Dairy Mart Road just after 1 a.m. Tuesday after a body was reported floating in the water, Muñoz said. Teams working with U.S. Customs & Border Protection were able to recover the body, but the person was already dead, she said.

The person has yet to be identified.

This is a developing story and will be updated.

Times staff writers Noah Goldberg, Priscella Vega, Hannah Fry and Hannah Wiley contributed to this report.

State officials have reported that nine people across California died in the biggest storm of the season, a major atmospheric river that left a trail of destruction due to dangerous winds and historic rains.

Among the deaths, four were killed by fallen trees in Northern California and two died in car wrecks in Southern California, officials said.

The storm initially whipped into Northern California on Saturday as a bomb cyclone — meaning it rapidly intensified — fueling dangerous winds on top of an already moisture-heavy system. Wind gusts along the Northern and Central California coast exceeded 90 and 100 mph in some areas, as the storm unleashed the beginning of a deluge of rain.

By Sunday and Monday, the system was walloping Southern California, dumping record-breaking rainfall, causing hundreds of mudslides and debris flows and forcing evacuations and water rescues.

The storm — fueled by El Niño, human-caused climate change and typical winter weather patterns — resulted in widespread power outages, road closures and flooding.

Here’s what The Times has been able to confirm about the nine people who died in the storm, in the order they occurred:

Feb. 1 in San Mateo County

A man in San Mateo County died Thursday after his vehicle hydroplaned and struck a tree, becoming the first storm-related death, according to Brian Ferguson, a spokesperson for the governor’s Office of Emergency Services. It wasn’t immediately clear if the heavy rain in the area at the time of the accident was brought on by the storm that hit the Northern California coast two days later.

Feb. 3 in Sacramento County

A woman in Sacramento County was killed by a fallen tree in her backyard, Ferguson said. Additional details were not immediately available from the Sacramento County Sheriff’s Office.

Feb. 4 in Sutter, Sacramento, and Santa Cruz counties

Three men were killed by downed trees in Northern California the next day.

Chad Ensey, 41, of Carmichael suffered blunt-force trauma and died at a hospital after a tree fell on him in his backyard amid strong wind, according to the Sacramento County Sheriff’s Office.

In the rural Santa Cruz County community of Boulder Creek, Robert Brainard III, 45, was killed when a tree fell on his home, officials there said.

And in Sutter County, 82-year-old David Gomes was found dead beneath a fallen redwood tree in his backyard, authorities said.

Feb. 5 in San Bernardino County

In San Bernardino County, a 69-year-old man died after losing control of his truck in Yucaipa, sending it into an embankment that submerged part of the vehicle, according to the California Highway Patrol. The San Bernardino man was taken to a hospital, where he died of his injuries. His identity wasn’t immediately available.

Ferguson also confirmed another traffic death in Southern California on this day, but the details weren’t immediately clear.

Feb. 5 in San Luis Obispo County

A 90-year-old woman in Los Osos died after the power went out at her home, where she was in hospice care and dependent on oxygen, according to San Luis Obispo County Sheriff’s spokesperson Tony Cipolla.

She called 911 after losing power and medics responded, but she died soon after, Cipolla said. He did not immediately provide her name.

Feb. 6 in San Diego County

A person was found dead in the Tijuana River along the Mexico border, according to Mónica Muñoz, a spokesperson for the San Diego Fire Department.

Firefighters were called to Dairy Mart Road just after 1 a.m. Tuesday after a body was reported floating in the water, Muñoz said. Teams working with U.S. Customs & Border Protection were able to recover the body, but the person was already dead, she said.

The person has yet to be identified.

This is a developing story and will be updated.

Times staff writers Noah Goldberg, Priscella Vega, Hannah Fry and Hannah Wiley contributed to this report.