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At least five people have died after a "bomb cyclone" associated with an atmospheric river swept through California on Tuesday and Wednesday — unleashing heavy rain, powerful winds and at least one tornado.

Threat level: Tens of thousands of customers were still without power on Wednesday evening, mostly in the Bay Area — where meteorologists on Tuesday recorded data indicating the strongest-ever March storm, judging by atmospheric pressure. The threat of flooding and mudslides remained for several places.

A screenshot of a tweet from the NWS LA office saying "#MontereyBay buoy today really took a dip. Sea level pressure dropped 24 millabar in just under 17 hours! Yikes! That's a meteorological💣(24 mb or more drop in 24 hours or less). And we had the winds to prove it. That round up will be coming shortly."

Photo: National Weather Service Los Angeles/Twitter

The big picture: The National Weather Service's Los Angeles office confirmed a tornado had touched down in Montebello during the storm on Wednesday morning. Another tornado was reported in Carpinteria on Tuesday, with winds estimated up to 75 mph, per the agency.

Tornadoes and bomb cyclones in both areas are rare and the NWS is assessing damages.

Zoom in: One person was killed and another was injured after a large tree fell onto a car in Walnut Creek, according to the Contra Costa County Fire Protection District.

Two people also died after being hospitalized in San Francisco on Tuesday in separate storm-related incidents, city officials said.

Another person was killed when a tree fell onto his vehicle in San Mateo County, the Contra Costa County coroner’s office confirmed per the Los Angeles Times.

A man was pronounced dead in Oakland Tuesday after a tree fell on the tent he was in near Lake Merritt, per the Times. 

By the numbers: More than 61,000 customers were without power in the state on Wednesday evening, per utility tracker poweroutage.us.

Where it stands: Rain showers were expected to taper off Wednesday night, with some showers lingering into Thursday morning along the Central Coast and in the mountains, per an NWS forecast discussion.

Another storm is possible next Tuesday and Wednesday, the weather service noted.

Context: Climate change is adding even more moisture to atmospheric rivers as ocean and air temperatures increase.

This enables them to dump higher rain and snow totals.

Contra Costa County Fire Protection District

California bomb cyclone leaves at least 5 dead

Tens of thousands of Californians are still without power this evening, mostly in the Bay Area, as flooding threat remains.

A person walks past an uprooted tree after a tornado touched down on March 22 in Montebello, California. Photo: Mario Tama/Getty Images

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An intensifying storm associated with a strong atmospheric river hit Central to Southern California with heavy rains, damaging winds and heavy mountain snowfall on Tuesday.

Of note: It's an unusually intense March storm for Central California, with satellite and radar imagery exhibiting swirling clouds around the center — almost resembling a tropical cyclone.

Data from the National Weather Service's Bay Area office indicates it's the strongest storm on record there in March, judging by atmospheric pressure. 

The pressure was much lower than had ever been recorded in the Bay Area for this month.

A screenshot of an NWS Bay Area tweet saying it has today recorded the lowest pressure ever for March during this storm

State of play: Nearly 179,000 customers were without power overnight with the Bay Area and Central Coast among the worst hit, per utility tracker poweroutage.us. The Santa Cruz hills were going dark in the afternoon with 80 mph winds.

The NWS' Los Angeles office issued a special weather statement on Tuesday evening due to the threat of landspouts, wind gusts up to 50 mph, and pea size hail, as it warned "torrential rain" was occurring that could trigger flooding.

"Gusty winds could knock down trees, tree limbs, and power lines, and blow around unsecured objects," the office warned.

The San Francisco Fire Department tweeted that it's responded "to numerous tree and wires down calls."

The Department of Public Works in San Diego County reported that a section of a key road in the area was closed due to flooding.

Meanwhile, satellite imagery on Tuesday afternoon showed the eye-like center of the storm making landfall near the San Francisco area, though the strongest winds were south of there.

What we're watching: High wind warnings and wind advisories were in effect throughout the state from San Francisco south to San Diego, with gusts up to 75 mph or greater possible in higher terrain.

Flood watches were in effect for central and southern California, where "[n]umerous flash floods are likely," the Weather Prediction Center said in a forecast discussion Tuesday.

Snowfall was expected to total up to 4 feet in the southern and central Sierra Nevada Mountains, putting strain on already buried infrastructure, given the record-breaking snowpack so far this year.

Of note: Departures to San Francisco International Airport were grounded due to wind from Tuesday afternoon into the evening, per the Federal Aviation Administration.

Context: With increasing ocean and air temperatures, climate change is adding even more moisture to atmospheric rivers, enabling them to dump higher rain and snow totals.

What we're watching: A very strong low pressure system that's offshore of San Francisco Bay will continue to bring high winds, heavy rain and heavy mountain snow for California and adjacent areas of the Southwest into Wednesday, per an NWS Weather Prediction Center forecast discussion Tuesday evening.

Precipitation was expected to change to snow over the Tejon Pass along Interstate-5, the NWS in Los Angeles warned.

Editor's note: This is a breaking news story. Please check back for updates.

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Storm-hit California slammed by another historic atmospheric river

With increasing ocean and air temperatures, climate change is adding even more moisture to atmospheric rivers.

A Cal Fire crew trenches a flooded road in an attempt to lower the water in Allensworth, Tulare County on Mar. 20. Photo: Luis Sinco/Los Angeles Times via Getty Images

Winter storms end SoCal's emergency water rules

The region is still under a water supply alert and significant challenges remain.

Madisyn Liles holding Luka, 1, watches as pumps remove flood water from her home on March 15 in Woodlake, California. Photo: Gina Ferazzi / Los Angeles Times via Getty Images

California officials were responding to the effects of another powerful atmospheric river that swept through the state — unleashing more historic rainfall, heavy snow and flash flooding.

The big picture: Evacuation orders, along with flood watches, warnings and advisories, were still in effect in several areas of the Golden State as officials continued to deal with levee breaches and flooded roads after the storm passed Wednesday.

This atmospheric river is at least the 11th to hit California since December and follows on the heels of the one that struck the state from Friday and into the weekend — and many of those areas were soaked again.

The National Weather Service's Los Angeles office reported preliminary data showing longstanding maximum daily rainfall records had been smashed, including at the airports of Santa Barbara, where 2.54 inches fell, and Los Angeles, where 1.97" was recorded.

Meanwhile, the southern Sierra Nevada appears to have recorded its largest-ever snowpack — more than 271% above its seasonal average, according to the California Department of Water Resources.

The U.C. Berkeley Central Sierra Snow Lab reported Wednesday morning that another 3.7" inches of snow had fallen.

"That takes us to 668" (16.97 m) of snowfall for the season (Oct 1 - current)," the snow lab said in a Twitter post.

"We are now 3" (7 cm) away from overtaking the '82/'83 winter as second snowiest at the lab and we should see that fall on Sunday."

State of play: The storm brought heavy precipitation across the state, particularly for the south Sierra Nevada, where heavy snow was projected above 8,000 feet, and the coastal areas of Southern California — where officials announced Wednesday emergency water restrictions were ending for some 7 million people.

Heavy rain combined with snowmelt in areas below 5,000 feet was projected to cause widespread flooding Wednesday.

The NWS said the "potent storm" that ramped up Tuesday was "expected to produce heavy mountain snow from the Sierra to the central/northern Rockies" as it swept through Wednesday.

State of play: Schools and roads remained closed across California due to the storm, which caused widespread power outages in the Bay Area. 

Some 43,000 customers in Santa Clara County and over 19,000 others in the neighboring San Mateo County were still without power on Wednesday night, per poweroutage.us.

The Sacramento, Salinas, and Merced rivers were among those to overflow as the storm swept south.

The cities of Porterville and Visalia in the San Joaquin Valley had declared states of emergency in response to the storm as Lake Success swelled in the storm, with nearly 19,800 cubic feet of water flowing in per second on Wednesday morning.

Context: Atmospheric rivers are narrow highways of moisture that can travel thousands of miles, from the tropics to mid-and-northern latitudes.

Studies show climate change is intensifying these events as warmer air carries additional water vapor and also yielding sharper swings between precipitation feasts and famine in California, per Axios' Andrew Freedman.

Editor's note: This article has been updated with additional details throughout.

California deals with flooding fallout from "potent" atmospheric river

New rainfall records were set in Los Angeles and several other cities, according to preliminary NWS data.

A California Department of Transportation worker patrolling a section of the Pacific Coast Highway, which closed due to flooding on Wednesday. Photo: Allen J. Schaben / Los Angeles Times via Getty Images

Editor's note: Follow the latest updates on this historic California storm.

California faced another atmospheric river event Tuesday that forecasters warn would bring heavy rains, widespread flooding and mountain snow to much of the state through Wednesday.

The big picture: As heavy rain fell Tuesday, officials warned the latest atmospheric river could "hammer" areas inundated by flooding in the earlier storm.

The National Weather Service (NWS) issued a "high risk" excessive rainfall outlook, the highest on its scale and a relatively rare designation.

The NWS warned of considerable "locally catastrophic flooding impacts" below 5,000 feet, with the heaviest rains moving down the coast from the San Francisco Bay Area, into the southern Sierra Nevada foothills and Los Angeles by Tuesday afternoon.

"Severe, widespread flash flooding is expected," the agency said in an online forecast discussion. "Areas that normally do not experience flash flooding will flood. Lives and property are in great danger from Tuesday into Wednesday."

Satellite image showing an atmospheric river event taking aim at California.

Satellite image showing an atmospheric river taking aim at California on March 14. Darker green colors indicate the highest moisture levels. Image: NOAA.

By the numbers: More than 320,000 customers were without power in California on Tuesday evening — mostly in the Bay Area, per Poweroutage.us.

The worst-affected Bay Area county was Santa Clara, where an estimated 125,000-plus customers had no electricity.

Threat level: The weather agency noted in another discussion that the latest atmospheric river contains an unusually high amount of moisture, and will remain parked over the same areas for extended periods. 

Forecasters warned of rapid snowmelt boosting water levels in rivers and streams, as well as extensive street flooding possible in downtown L.A.

"We are anticipating that there will be both flash flooding and river and stream flooding and the greatest risk for significant flooding will be across the western slope of the southern Sierra, and also along portions of the central and south coast of California," Megan Syner, a meteorologist with the NWS, told Axios in an interview. 

Syner said Santa Cruz, the Santa Lucia and San Raphael mountain ranges, as well as higher elevations in Los Angeles and San Bernardino counties may see the heaviest rains from this event. 

Forecasters are watching Monterey County closely, where the California National Guard helped rescue 56 people after the Pajaro River's levee breached early Saturday.

Damaging winds and power outages are likely, especially in Central California. San Francisco International Airport recorded a wind gust of 74 mph, which is hurricane force, shortly before noon local time. 

State of play: Local schools and roads were closed and evacuation orders and warnings were in effect for communities along the Pajaro River and other rivers due to rising floodwaters and the threat of further inundation.

Luis Alejo, chair of the Monterey County Board of Supervisors, tweeted Monday night that a breach area along the Pajaro Levee "had grown from 120 wide to 400 feet wide," but a temporary rock and sand wall "will prevent the breach from getting wider" and "slow the flow of water into the Pajaro community."

Meanwhile, the southern Sierra Nevada appears to have recorded its largest-ever snowpack — more than 250% above its seasonal average, according to the California Department of Water Resources.

The U.C. Berkeley Central Sierra Snow Lab reported Tuesday morning that another 13.6" of snow had fallen "and that takes us to within 7" of the winter 1982/1983 total, which is currently second snowiest all-time" on record at the central Sierra snow laboratory.

What we're watching: Heavy rains and high-elevation snow are expected to continue into Wednesday from this "Pineapple Express" atmospheric river.

Of note: The moisture for this particular storm originates near Hawaii.

Context: Atmospheric rivers are narrow currents in the air that can carry vast amounts of water vapor thousands of miles, from the tropics to mid-and-northern latitudes — and they've lashed California on more than a dozen occasions this year.

"It really is like a river in the sky," Syner said.

Studies show climate change is intensifying these events since warmer air carries additional water vapor. Climate change is also yielding sharper swings between precipitation feasts and famine in California.

Latest atmospheric river brings "catastrophic" flood risk to California

Officials warn the storm could cause "locally catastrophic" flooding, and poses life-threatening risks.

A water rescue officer walks through flooded Pajaro neighborhood streets checking on residents who have not evacuated since a levy breech that flooded the community caused by an atmospheric river storm that slammed California on March 13. Photo: Melina Mara/The Washington Post via Getty Images

Storms associated with atmospheric rivers have dumped record amounts of rain and snow in California this winter, resulting in flooding and other hazards.

The big picture: Atmospheric rivers direct tropical moisture, often from more than 1,500 miles away, toward the Golden State, where it is wrung out in the form of heavy precipitation. 

Atmospheric rivers are long, narrow highways of moisture, typically located at about 10,000 to 15,000 feet above the surface. They can travel thousands of miles and are responsible for 30-50% of the wet season precipitation along the West Coast of the U.S., according to NOAA. 

A strong atmospheric river can transport an amount of water vapor that is “roughly equivalent to 7.5–15 times the average flow of liquid water at the mouth of the Mississippi River,” NOAA has found.

Scientists have only recently gained a greater understanding of the role that atmospheric rivers play in West Coast storm events, and observed them affecting other regions of the world as well. 

Diagram of an atmospheric river hitting California.

Diagram of an atmospheric river hitting the West Coast. Image: Sarah Grillo/Axios

During the past few months, hurricane hunters operated by the Air Force and NOAA have been investigating atmospheric rivers over the Pacific Ocean and providing added data for computer models to refine their projections. 

'Threat level: This winter, California has been hit by more than a dozen atmospheric river events, many of them strong ones that have dumped upwards of 100 inches of snow at a time in the Sierra Nevada mountains, and about a foot of rain at lower elevations. 

While all this precipitation has helped ease, though not eliminate, the record drought affecting the state, there can be too much of a good thing. 

With an epic snowpack 200 inches deep in some places, reservoirs that are rising toward full levels and rivers running high, any additional atmospheric river events could cause serious flooding. 

This is particularly the case for warm atmospheric rivers, which can raise snow levels and cause rain to fall on top of the existing snow, releasing some of its water content.

Damaging flooding has already occurred in Central and Northern California during mid-March from atmospheric river events, and more may be on the way. 

Between the lines: Climate change is adding even more moisture to atmospheric rivers, enabling them to dump higher rain and snow totals. 

This is occurring because ocean temperatures are increasing, causing more heat and moisture to be transferred into the atmosphere and made available to storm systems. 

In addition, with each 1°C (1.8°F) increase in air temperatures, a particular air mass can hold at least 7% more moisture. 

Individual storms associated with atmospheric rivers can pull in even more water vapor than this, making damaging rain and snowfall more likely. 

California is still in a long-term severe drought, particularly given its depleted groundwater supplies. 

The bottom line: Studies also show that climate change raises the odds of weather whiplash events from drought to flooding and back again. 

This is noteworthy since California was already known for its feast or famine precipitation regime. 

Go deeper: Next in parade of atmospheric rivers set to slam storm-hit California

In photos: Atmospheric river floods a storm-ravaged California

Atmospheric rivers force California to manage floods during drought

Next atmospheric river brings "high risk" of flooding to soaked California

epic snowpack 200 inches deep in some places

Next in parade of atmospheric rivers set to slam storm-hit California

What is an atmospheric river? Weather event behind California floods, record snow

These weather systems can transport tropical moisture thousands of miles.

Flooding taking place in Central California from atmospheric river storms in March 2023.

Flood waters of Deer Creek spread near Porterville, Calif. on March 10. Photo: David McNew/Getty Images. 

At least two storm-related deaths were confirmed by state officials Friday as a powerful atmospheric river storm brought heavy rain and thunderstorms, and left thousands across Northern and Central California without power.

The big picture: The National Weather Service has warned of "copious amounts of heavy snow" in the mountains and potential flooding from a "high risk" of excessive rainfall. It's also increasingly likely that another significant atmospheric river event hitting central and northern California beginning on Monday.

Dangerous conditions continue this weekend, with rain and melting snow causing "widespread considerable flooding impacts" in some regions, per NWS. 

The current system is the latest in a series of storms that have battered the Golden State this year, delivering damaging blizzards and downpours. 

The latest: More than 22,800 people remain without power in California at 9 a.m. ET on Sunday, according to PowerOutage.us.

A flood warning remains in place through Sunday night for the Salinas river, affecting Monterey county, NWS said Saturday night. Evacuation orders were issued to some areas around the river.

In Monterey County, a breach in a river embankment led to massive flooding overnight, officials said Saturday.

First responders conducted at least 56 rescues in the area overnight, the California National Guard reported Saturday afternoon. The entire town of Pajaro is now under some level of water, the Los Angeles Times notes.

Monterey County also advised Pajaro residents not to drink their tap water after potentially contaminated flood water may have gotten into the water district's wells.

Rainfall totals showed the damage from Friday. Rocky Butte in San Luis Obispo County saw 11.58 inches, per the National Weather Service. Light rain was expected to continue overnight.

The storms flooded rural communities, small highways, creeks and rivers, AP reports.

Much of California is still under some type of flood warning, watch or advisory, per the NWS. 

Flood advisories in Santa Barbara, Ventura, and Los Angeles counties expired overnight, according to the NWS. The flash flood warnings for San Luis Obispo County were also canceled, but the county still has some evacuation orders and warnings listed for the area.

Kings Canyon and Sequoia National Parks remained closed Saturday.

President Biden on Friday also approved an emergency declaration for California, authorizing FEMA to "identify, mobilize, and provide at its discretion, equipment and resources necessary to alleviate the impacts of the emergency."

Later Friday, California Gov. Gavin Newsom (D) signed an executive order to suspend regulations on permitting so that water from the storm can be captured and used to recharge state groundwater supplies.

Details: The latest barrage hit the Sierra Nevadas' Kern River Valley especially hard on Friday, with officials ordering evacuations for multiple areas in the county. The water flow was "a threat to life and/or property," the Kern County Sheriff's office tweeted.

Footage shared online showed a robust rise in a river in Kernville amid the NWS' predictions of "extreme" flash flooding — the highest threat level NWS officials can issue.

Rising rivers also forced evacuations in the coastal Santa Cruz County as mudslides and heavy rains created hazards on the road. 

Soldiers with the state's National Guard were deployed to the region Friday afternoon to support state and local first responders.

Context: Atmospheric rivers are potent because narrow currents in the air can carry vast amounts of water vapor thousands of miles — and they have hammered California so far this year.

Climate change is adding even more moisture to atmospheric rivers, enabling them to dump higher rain and snow totals, Axios' Andrew Freedman notes.

Threat level: "A dangerous excessive rainfall event is underway across much of Central California," the NWS said early Friday, adding that up to nine inches of rain could fall on snowpack and already saturated soil, causing "widespread and severe flooding impacts."

The latest storm arrived as communities in the San Bernardino Mountains were still reeling from earlier snowstorms that have killed at least 12 people since Feb. 23, per the Los Angeles Times.

Between the lines: High-risk outlooks are rare — once a decade or more for some locations — and show that the NWS is worried about dangerous weather.

A screenshot of a Yosemite National Park tweet saying it'll stay shut until at least March 16 due to the storms.

What to watch: A new major storm system arrives early next week, "delivering another round of excessive rainfall & heavy mountain snow to the West Coast," the NWS said.

Then, come midweek, more heavy rain and snowmelt could lead to fresh flooding, "particularly in low elevations and areas with shallow snowpack," per NWS.

Editor's note: This article has been updated with new details throughout.

storms that have battered the Golden State this year,

Thousands without power as strong atmospheric river floods California

President Biden on Friday ordered Federal assistance to supplement local response efforts due to the emergency conditions.

 woman braves the flooded streets alongside splashing trucks as an atmospheric river storm slams California in Salinas, California 

A woman braves the flooded streets as an atmospheric river storm slams California. Photo: Melina Mara/The Washington Post via Getty Images

The deadly Tropical Cyclone Freddy is threatening to make landfall in Mozambique again after lashing Madagascar for a second time as it continued its historic run Monday.

The big picture: Thursday marks 34 days since Freddy formed. It "does appear to be a new record holder for 'longest-lasting' recorded tropical cyclone," per a statement Monday from Randall Cerveny, the World Meteorological Organization's rapporteur for weather and climate extremes.

The WMO will open an investigation to confirm that record once the storm has dissipated.

Freddy has already set the Southern Hemisphere record for the highest accumulated cyclone energy (ACE), an index measuring wind energy associated with a tropical cyclone over its lifetime, per NASA.

State of play: Freddy became a named storm off the Australia's northern coast on Feb. 6.

It "crossed the entire South Indian Ocean" and made landfall in Madagascar on Feb. 21 before striking Mozambique three days later, per the WMO.

"The storm spent several days tracking over Mozambique and Zimbabwe, bringing  heavy rains and flooding," the UN weather agency said.

Freddy, "longest-lasting" tropical cyclone, to hit Mozambique for 2nd time

The deadly storm has killed more than 20 people and displaced thousands of others during its record run.

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