Southern California was pounded with rain overnight as the third and final storm in a series dumped more than 4 inches in some places.

Long Beach set a new rainfall record with 3.97 inches, with some neighborhoods receiving intense downpours of up to 3 inches per hour. The previous record for the city was 2.06 inches, set in 1967.

Long Beach Mayor Robert Garcia told KPCC that conditions have improved this morning, but there is damage to assess.

"We've had trees fall on some cars, we had some trees fall into private property, and we have had some flooding in both public and private buildings. And so as far as the damage it will take us a couple of days to fully understand the extent," Garcia said.

Long Beach rescue crews had their hands full Sunday. Eight people were rescued from vehicles. The fire department rescued two male teens from a raft in the Los Angeles River channel. They were transported to a local hospital.

"We were anticipating severe rain but not a record rainfall," said Jake Heflin, spokesman for the Long Beach Fire Department.

Ojai saw the most rain, topping 4 inches, according to the National Weather Service.

Sleet and hail contributed to a 15-car collision on the Grapevine just before 4:30 a.m. Monday morning, according to Officer Brian Moore of the CHP. The collision has since been cleared, with nine injured and five hospitalized with minor injuries. Now, snow is falling and sticking to the road, with CHP officers escorting drivers through the Grapevine and keeping them bunched together – doing so generates more heat and helps melt the snow on the road, Moore told KPCC.

In L.A., emergency crews rescued 12 people and two pets from rain-swept flood control channels and riverbeds over the last 24 hours, according to L.A. Fire Department spokesman Brian Humphrey. Crews also responded to 172 weather-related incidents, including flooding, debris flow, fallen trees and transformer fires. No deaths, serious injuries or loss of structures have been reported.

The immediate storm impact began to subside Monday morning, but the period after a storm ends has historically been the deadliest time, as people head to flood channels to watch the water flow, Humphrey said.

A flash flood warning for much of Southern California was extended through 6 p.m. Monday. Isolated thunderstorms are possible, and rain was predicted to fall at rates of a half-inch to an inch per hour, continuing the threat of debris flows in recent burn areas, according to the weather service.

Rockslides forced the closure of two different roads in Malibu. Topanga Canyon Road was closed from Pacific Coast Highway to Grand View Drive, and Malibu Canyon Road from Francisco Ranch to Piuma Road, according to the California Highway Patrol’s incident log.

The southbound lanes of State Route 14 were closed at Escondido Canyon Road, with reports of a boulder the size of a vehicle in the roadway. Flooding was reported in the 2900 block of San Francisquito Canyon Road.

The 710 and 110 freeways were open again as of early Monday. Both had been closed due to flooding, with 2 to 3 feet of water reportedly covering the 710 at one point.

Evacuations and Closures by Area

DUARTE

• 180 homes under mandatory evacuation orders near the Fish Fire burn area
• Duarte Community Center at 1600 Huntington Drive has been set up as a shelter — meals are being provided and animals accommodated through a Los Angeles County Animal Control mobile shelter on site
• Minor mud and debris flows reported along Melcanyon Road
• Road closures: Royal Oaks and Greenbank, Bettyhill and Conata, Royal Oaks and Mel Canyon, eastbound Fish Canyon at Mel Canyon, westbound Fish Canyon at Mel Canyon, Mountaincrest and Deerlane, and Brookridge and Tannencrest
• Valley View Elementary School closed for the day
• Sandbags and sand available 24 hours a day at L.A. County Fire station 44, located at 1105 Highland Avenue
• Residents have been encouraged to sign up for Nixle alerts here.

GLENDORA

• The city downgraded its alert system from Orange to Yellow, which means voluntary evacuations have been lifted. The city advised that heavy downpours are still possible, but the most significant threat has passed.

SANTA CLARITA

• Evacuations for residents in the Sand Canyon and other Santa Clarita Valley burn areas were lifted at 10 a.m. Monday morning.
• A shelter has been set up at Canyon High School at 19300 Nadal St. Small animals can be taken to the Castaic Animal Shelter at 31044 Charlie Canyon Road, while livestock can be taken to Pierce College at 6201 Winnetka Ave. in Woodland Hills
• Road closures: Sand Canyon and Lost Canyon (soft closure), Placerita Canyon and 14 Freeway, Sand Canyon and Placerita Canyon into Bear Divide (hard closure), Little Tujunga Road is inaccessible. Roads leading into the Val Verde area are open.

ORANGE COUNTY

• A voluntary evacuation order at the Silverado Canyon burn area has been lifted
• Sandbags are available for residents in unincorporated county areas — call OC Public Works at 714–955–0200

CAMARILLO SPRINGS

• Voluntary evacuation order lifted Sunday for residents in Divisions A, B, C & D

CAMARILLO

• Road closures: 101 northbound onramp at Springville, southbound Las Posas Road from Fifth Street to Laguna Road, Cawelti between Las Posas Road to South Lewis Road

OXNARD

• Road closures: Pleasant Valley Road closed between Wood Road and Airport Way, No. 2 Lane of East Vineyard Avenue between Lambert and Central

OJAI

• Road closures: Highway 33 from Wheeler Gorge to Lockwood Valley Road

Gas Advisory

SoCal Gas, meanwhile, advised residents to conserve natural gas by lowering thermostats to 68 degrees, waiting a day to use major gas appliances and washing laundry with cold water.

The company's largest underground gas storage field is the one near Porter Ranch, which sprang the nation's largest ever gas leak in late 2015, and remains closed while it undergoes safety inspections.

Individual homes and businesses that are the core customers of SoCal Gas are not at immediate risk of having their supplies cut off. That's because it would take days or weeks to restore service to so many individual customers and their appliances.

But SoCal Gas is putting large gas users like refineries and power plants on notice that their supply of gas could be cut off if gas supplies fall too low. Those are so-called non-core customers who buy their own gas from out of state but receive it through SoCal Gas pipelines.

This is at least the second gas supply advisory that SoCal Gas has put out this winter warning big customers of potential cutoff and asking homes and small businesses to conserve supplies.