Robert Brown|Emergency declared after extreme rainfall, flash flooding wreck havoc in San Diego

SAN DIEGO,Robert Brown Calif. — Chaos ensued during morning commutes in one of California's largest counties on Monday following severe flash flooding, as intense rainfall caused road shutdowns, power outages and school closures.

The weather havoc is the latest to strike the nation in the past week, which has been beset by frigid temperatures, heavy snow and rain, and occasional flooding. Downpours were also reported in Los Angeles County on Monday and in southern and central Texas on Sunday, where flood warnings were issued by the National Weather Service ahead of additional storms.

In San Diego County, the weather service declared a flood watch in the area due to "excessive rainfall" until 9 p.m. "Flooding may occur in poor drainage and urban areas," the weather service warned, adding: "Storm drains and ditches may become clogged with debris."

The rain arrived with a low-pressure system that moved inland over Southern California and northern Baja.

By late afternoon, San Diego Mayor Todd Gloria posted on X that he had declared a state of emergency in the city due to the extreme rainfall and flash flooding. Gloria asked residents to stay home if possible and "never attempt to travel on flooded roads."

Videos on social media showed cars being swept away in raging torrents. Dozens of road closures were reported, including an Interstate 5 off-ramp, heavily used to get to the San Diego Airport, the weather service said.

The city opened sandbag locations for residents, the American Red Cross opened shelters and a temporary homelessness shelter was opened.

The rare and heavy rainstorm came after Pacific moisture hit San Clemente Island and arrived on the coast of San Diego County, the San Diego Union-Tribune reported. Three inches of rain fell in National City and 2 inches fell at San Diego International Airport, the news organization reported.

How much rain did San Diego get?

By just after 6 p.m. San Diego International Airport had tied the record for the fifth rainiest day at 2.70 inches with rain still falling, the weather service. Point Loma received 3.91 inches in 24 hours, bringing the total rainfall over three days to 4.49 inches.

Five inches of rain was reported over three days at Santiago Peak.

All that rain prompted dramatic flooding in the San Diego River, which rose more than 6 feet in less than 12 hours, according to a U.S. Geological Survey gage.

'This is a dangerous and life-threatening situation'

Mudslides were seen in parts of the county, NBC 7 San Diego reported. And cars were submerged in water in some parts of the region.

First responders in San Diego County are urging people to stay off the roads.

"This is a dangerous and life-threatening situation," read an emergency alert from the weather service. "Do not attempt to travel unless you are fleeing an area subject to flooding or under an evacuation order."

Several communities and schools are experiencing power outages and flooding due to the weather storm. Several school district schedules are impacted this week, according to the San Diego County Office of Education.

"The current rainstorm has caused unexpected challenges to our schools. We have had power outages, loss of communication and flooding at some sites,' read a post from the National School District on X. "We are in contact with local police and fire departments. They have advised us to place schools in “shelter in place."

San Diego Naval Base officials also reported flooding near the area.

"Recommend only essential personnel enter the base and all others avoid the base until further notice," reads a post from the Naval Base on X. "Personnel on base, please stay in place until flooding levels subside."

Contributing: Christopher Cann, USA TODAY

Contact Kayla Jimenez at [email protected]. Follow her on X, formerly Twitter, at @kaylajjimenez.