MONTECITO, Calif. -- A storm that slammed a California coastal community is over. The search for its victims isn't.

Authorities in Santa Barbara County were still trying to reach new areas and dig into the destruction to find dead, injured or trapped people after a powerful mud flow swept away dozens of homes.

At least 15 people were confirmed dead Tuesday, at least 28 were injured and at least 50 had to be rescued by helicopters. Four of the injured were reported in severely critical condition.

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Authorities said 24 people remained unaccounted for as of Wednesday afternoon.

Those numbers could increase when the search is deepened and expanded throughout the day, with a major search-and-rescue team arriving from nearby Los Angeles County and help from the Coast Guard and National Guard along with law enforcement. They'll focus first on finding survivors.

"Right now our assets are focused on determining if anyone is still alive in any of those structures that have been damaged," Santa Barbara County Sheriff Bill Brown said.

Sheriff's deputies say 100 single family residences have been destroyed, 20 dwellings were damaged and 1,500 others were threatened by the storm. Eight commercial buildings were destroyed, 20 were damaged and 200 others were threatened.

He said it's likely they'll find more people amid that destruction.

Height mud reached in this Montecito, California home can be seen clearly in this image from period after deadly mudslides raced through the wealthy community CBS Los Angeles

The search for the missing - whose numbers are uncertain - was continuing through the night and was to intensify after daylight Wednesday, authorities said.

Most deaths were believed to have occurred in Montecito, said Santa Barbara County spokesman David Villalobos.

The wealthy enclave of about 9,000 people northwest of Los Angeles is home to such celebrities as Oprah Winfrey, Rob Lowe and Ellen DeGeneres.

Winfrey's home survived the storm and slides. In an Instagram post, she shared photos of the deep mud in her backyard and video of rescue helicopters hovering over her house.

"What a day!" Winfrey said. "Praying for our community again in Santa Barbara."

A mud-caked 14-year-old girl was among the dozens rescued on the ground Tuesday. She was pulled from a collapsed Montecito home where she had been trapped for hours.

14-year-old is seen being rescued from deadly mudslides in Montecito, California on January 9, 2018 CBS Los Angeles

Video captured the terrifying moments before a flash flood came down a Montecito street as a man was trying to hustle his parents away from danger. CBS Los Angeles reports Marco Farrell was trying to get his parents out of their home, and was waving another driver away from the area, when the flood began moving its way down the street.

"Turn around! The flash flood's right there! The flash flood's right there! Get out of here, go," he could be heard yelling, his voice breaking in panic.

The rest of the video ended chaotically as Farrell ran back into a house, and urged his mother to wake up his father.

Twenty people were hospitalized and four were described as "severely critical" by Dr. Brett Wilson of Santa Barbara Cottage Hospital.

Video from the Coast Guard shows a family-of-five, including a newborn, two other small children, their mother and father and the family's two dogs, being rescued from a rooftop, reports CBS Los Angeles.

Some families reportedly waited on the roof for 45 minutes and watched their cars roll away in the mud, CBS Los Angeles says.

One neighbor said he found a two-year-old trapped several feet under the mud. He described the toddler as a "muddy doll."

The mud was unleashed in the dead of night by flash flooding in the steep, fire-scarred Santa Ynez Mountains. Burned-over zones are especially susceptible to destructive mudslides because scorched earth doesn't absorb water well and the land is easily eroded when there are no shrubs.

The torrent arrived suddenly and with a sound some likened to a freight train as water carrying rocks and trees washed away cars and trashed homes.

Thomas Tighe said he stepped outside his Montecito home in the middle of the night and heard "a deep rumbling, an ominous sound I knew was ... boulders moving as the mud was rising."

Scene in Montecito, California following deadlky musdlies on January 9, 2018 CBS Los Angeles

Two cars were missing from his driveway and he watched two others slowly move sideways down the middle of the street "in a river of mud."

In daylight, Tighe was shocked to see a body pinned by muck against his neighbor's home. He wasn't sure who it was.

Authorities had been bracing for the possibility of catastrophic flooding because of heavy rain in the forecast for the first time in 10 months.

Evacuations were ordered beneath recently burned areas of Santa Barbara, Ventura and Los Angeles counties. But only an estimated 10 to 15 percent of people in a mandatory evacuation area of Santa Barbara County heeded the warning, authorities said.

U.S. Highway 101, the link connecting Ventura and Santa Barbara, looked like a muddy river and was expected to be closed for two days.

The worst of the rainfall occurred in a 15-minute span starting at 3:30 a.m. Montecito got more than a half-inch in five minutes, while Carpinteria received nearly an inch in 15 minutes.

"All hell broke loose," said Peter Hartmann, a dentist who moonlights as a news photographer for the local website Noozhawk. "Power lines were down, high-voltage power lines, the large aluminum poles to hold those were snapped in half. Water was flowing out of water mains and sheared-off fire hydrants."

Hartmann watched rescuers revive a toddler pulled unresponsive from the muck.

"It was a freaky moment to see her just covered in mud," he said.

Hartmann said he found a tennis trophy awarded in 1991 to a father-son team his wife knows.

"Both of them were caught in the flood. Son's in the hospital, dad hasn't been found yet," he said, declining to name them.

The first confirmed death was Roy Rohter, a former real estate broker who founded St. Augustine Academy in Ventura. The Catholic school's headmaster, Michael Van Hecke, announced the death and said Rohter's wife was injured by the mudslide.

Montecito is beneath the scar left by a wildfire that erupted Dec. 4 and became the largest ever recorded in California. It spread over more than 440 square miles and destroyed 1,063 homes and other structures. It continues to smolder deep in the wilderness.