(CNN) The founder of a Catholic school is among the 17 people killed in deadly mudslides and flooding in Southern California. Hundreds of rescuers and dogs continued searching for people Wednesday, slogging through mud and debris.

Roy Rohter, 84, and his wife, Theresa, were swept from their Montecito home, the headmaster said. Theresa was rescued, said Michael Van Hecke, headmaster of St. Augustine Academy in Ventura, which Rohter founded in 1994.

Authorities have not confirmed the names of the dead. Children are among the victims, said Santa Barbara County fire spokesman Mike Eliason.

Heavy rains early Tuesday caused rivers of mud and debris to run down from hillsides in Santa Barbara County, demolishing homes in the affluent seaside community of Montecito weeks after wildfires in the area . Many people are on edge, awaiting news about missing loved ones.

Latest developments

• Deadly storm: The 17 deaths were reported in Santa Barbara County, authorities said.

• More missing: Officials said 17 people were unaccounted for.

• Rescue operation: More than 500 first responders and 10 dogs continued to search for people in Santa Barbara County.

• Trapped residents evacuated: First responders used a helicopter to rescue some of 300 residents trapped by debris blocking their way out of Montecito's Romero Canyon area, Santa Barbara County Sheriff Bill Brown. Some residents wanted to stay in their homes, Brown said.

• Hundreds of calls: As the storm hit hard between 3 and 6 a.m. Tuesday, sheriff's office dispatchers handled more than 600 phone calls for assistance, Brown said.

A Coast Guard helicopter crew pulls a person onto a roof after mud overtook a house in Carpinteria.

• Injured: Twenty-eight people were hurt in Santa Barbara County, officials said.

• Destruction: Floodwaters and mudslides destroyed 100 homes and damaged another 300 residences in Santa Barbara County.

• Road closed: US 101 in parts of Montecito and Santa Barbara will remain closed for at least 48 hours because of the muddy debris covering it, authorities said Tuesday.

Photos: Deadly mudslides in Southern California An aerial view of Montecito, California, shows mudflow and debris on Wednesday, January 10, 2018. Heavy rains unleashed deadly mudslides Tuesday that damaged or swept away dozens of homes in Southern California. Hide Caption 1 of 18 Photos: Deadly mudslides in Southern California A damaged home is seen in Montecito on January 10, 2018. Hide Caption 2 of 18 Photos: Deadly mudslides in Southern California Part of a structure sits in a tree after being knocked off its foundation by a Montecito mudslide on January 10, 2018. Hide Caption 3 of 18 Photos: Deadly mudslides in Southern California Emergency personnel carry a woman from a collapsed house after a mudslide in Montecito on January 9, 2018. Hide Caption 4 of 18 Photos: Deadly mudslides in Southern California Kerry Mann navigates the large boulders and mudflow that destroyed her friend's home in Montecito. Hide Caption 5 of 18 Photos: Deadly mudslides in Southern California A view of the 101 freeway from Olive Mill Road in Montecito. Hide Caption 6 of 18 Photos: Deadly mudslides in Southern California Phillip Harnsberger crosses through mud from a flooded creek in Montecito on January 9, 2018. Hide Caption 7 of 18 Photos: Deadly mudslides in Southern California Mud fills the interior of a destroyed car in Burbank on January 9, 2018. Hide Caption 8 of 18 Photos: Deadly mudslides in Southern California Runoff water from a creek floods Highway 101 in Montecito on January 9, 2018. Flooding forced many heavily traveled roads to close. Hide Caption 9 of 18 Photos: Deadly mudslides in Southern California Reilly, a search dog with the Santa Barbara County Fire Department, looks for victims in Montecito on January 9, 2018. Hide Caption 10 of 18 Photos: Deadly mudslides in Southern California A firefighter clears debris in Los Angeles on January 9, 2018. Hide Caption 11 of 18 Photos: Deadly mudslides in Southern California A van is stuck in the mud in the Sun Valley neighborhood of Los Angeles on January 9, 2018. Hide Caption 12 of 18 Photos: Deadly mudslides in Southern California A police vehicle drives across a flooded side road in Montecito, near the San Ysidro exit of Highway 101 on January 9, 2018. Hide Caption 13 of 18 Photos: Deadly mudslides in Southern California Mud covers a road in Burbank on January 9, 2018. Hide Caption 14 of 18 Photos: Deadly mudslides in Southern California Los Angeles firefighters work amid floodwaters and mud on January 9, 2018. Hide Caption 15 of 18 Photos: Deadly mudslides in Southern California A member of the Long Beach search and rescue team looks for survivors in a car in Montecito on January 9, 2018. Hide Caption 16 of 18 Photos: Deadly mudslides in Southern California Mud washes away personal belongings in the Sun Valley neighborhood of Los Angeles on January 9, 2018. Hide Caption 17 of 18 Photos: Deadly mudslides in Southern California Rushing rainwater fills the Los Angeles River near downtown Los Angeles. Hide Caption 18 of 18

'I just want to find my friend'

In Montecito, east of Santa Barbara, home after home is damaged or encircled by mounds of mud, furniture and fallen trees.

Diane Brewer has hopes of finding her missing friend Josie Gower, 69. Gower was at home with her boyfriend early Tuesday when a mudslide swept through the neighborhood.

Mud fillls a street Tuesday in Burbank, California, destroying cars and damaging property.

"For some reason, she opened the front door" and was swept away, Brewer said.

The boyfriend also was carried away and became stuck between boulders before being rescued, Brewer said.

Debris surrounds a house Wednesday in Montecito, California.

Brewer and others planned to search the property.

"I just want to find my friend," Brewer said, in tears.

Hours later, Brewer confirmed Gower's death.

"Josie grew up right around the corner from me; she was 15, I was 5," Brewer said.

She added: "It was always a full a life with Josie. Now, it's just a hole."

The missing

Family members waited for word about their missing loved ones. Many turned to social media in their search.

James and Alice Mitchell, an elderly couple from Montecito, are among those missing, the couple's granddaughter, Sarah Weimer, told CNN Wednesday. Weimer said her mother was in Montecito helping with the search.

Rebecca Riskin, the founding partner of Riskin Partners, a Montecito real estate company, is also missing, a relative, Lynne Creighton said.

Riskin began selling real estate in Los Angeles. In 1990, she moved to Montecito, where she climbed to the top of real estate industry, according to the biography on her firm's website.

'River of mud'

Thomas Tighe was outside his Montecito home when he heard "a deep rumbling, an ominous sound I knew was ... boulders moving as the mud was rising," he told CNN affiliate KCAL.

He saw two cars moving sideways down the middle of the street "in a river of mud."

Peter Hartmann said the destruction was everywhere.

"There were gas mains that had popped, where you could hear the hissing," he told the TV station.

"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."

Before the storm hit, Santa Barbara issued mandatory evacuations for 7,000 people , including in parts of Carpinteria, Montecito and Goleta, which are below areas scorched by wildfires, county spokeswoman Gina DePinto said.

"While some residents cooperated with the evacuations, many did not. Many chose to stay in place," said Brown, the sheriff.

Sheriff deputies spent Monday conducting door-to-door evacuations for 7,000 people in a mandatory evacuation area. But the area where homes were destroyed, south of Highway 192, was not in a mandatory evacuation zone.

View from the air in Montecito. Areas that had been roadways, driveways, and homes, are now unrecognizable due to the large amount of mud and debris flows. pic.twitter.com/dbsUPw3mrL — VenturaCoAirUnit (@VCAirUnit) January 9, 2018

Rescue personnel still have areas to search, Brown said.

"It was literally a carpet of mud and debris everywhere, with huge boulders, rocks, (downed) trees, power lines, wrecked cars -- lots of obstacles and challenges for rescue personnel to get to homes," Brown said.

Oprah: Debris is 'everywhere'

Oprah Winfrey posted a video on social media of her trudging through the mud in the yard of her Montecito home.

"There used to a fence right here,"she said, pointing in the direction of a neighbor's home. "My neighbor's house, devastated." Winfrey said debris is "everywhere."

She said her home had minor damage, but it pales in comparison to what her her neighbors suffered.

The debris also shut down parts of the oceanside US 101, a major thoroughfare connecting Northern and Southern California.

A stew of floodwater, mud, tree limbs and other debris covered the highway in Montecito, making it impassable. Some cars were left on the highway, mired wheel-deep in the muck.

The US 101 Freeway at the Olive Mill Road overpass flooded with runoff water from Montecito Creek. pic.twitter.com/SjaSOgOFMm — SBCFireInfo (@EliasonMike) January 9, 2018

As workers clear debris to make areas accessible, more damage is revealed. Along Montecito's Coast Village Road, the mudslide overturned trees and covered the pavement. At one spot, a car appeared to be sheared in half -- its front half pointed skyward, jammed against a pile of muddy wreckage.

The remains of a car are jammed against muddy debris Tuesday in Montecito in Santa Barbara County.

More than 1 inch of rain per hour

The rain fell at more than 1.5 inches per hour at one point early Tuesday in parts of Southern California. About a half inch per hour is enough to start mudslides, said Robbie Monroe of the National Weather Service in Oxnard.

The downpour fell in areas charred by recent wildfires, which burned vegetation that otherwise could make the terrain more resistant to mudslides.

The Thomas Fire -- the largest wildfire in California's recorded history -- has burned more than 281,000 acres in Santa Barbara and Ventura counties since it began in early December. It was 92% contained, and officials don't expect full containment until later this month.

This in front of the @FSSantaBarbara above #butterflybeach. Debris from our neighborhood no doubt. pic.twitter.com/IMa3Iypb1s — Benjamin Hyatt (@caffeineben) January 9, 2018

Montecito and Carpinteria are especially vulnerable to mudslides because the steep terrain in some places goes from thousands of feet above sea level to sea level in "a matter of just a few miles," said Tom Fayram, a deputy public works director with Santa Barbara County.