A late summer storm system that brought heavy rain to parts of the Southland triggered mudslides in San Bernardino and washed away a vehicle in the Inland Empire, triggering a frantic search for a 2-year-old boy.

Relatives are asking for help finding Xavier Padilla, who was swept away in the floodwaters around 6:30 p.m. Thursday near Main Street in Barstow when he was in the car with his father, Brandon, according to KABC.

"We have a bunch of volunteers out here who are still looking," Xavier's aunt, Leanna, told the station. "If you guys can, if you live in the area, if you have bright lights ... anything that can help us look through the dirt, the mud -- anything to help us look for him and find him, we greatly appreciate it."

Xavier's disappearance occurred amid a late summer monsoon storm system -- remnants of Tropical Storm Mario -- that brought sweltering heat and unpredictable showers and thunderstorms to the region.

Parts of Cedar Falls Road at Camp Cedar Falls was buried in a mudslide Thursday afternoon, trapping drivers who had to wait for hours to be freed, according to a California Department of Transportation District 8 Facebook post.

"We have made a lot of progress in the last few hours and are getting to people best we can," Caltrans posted on Facebook just before midnight Thursday. "We are actually almost to the largest group of stuck motorists."

The storm was expected to drop up to a quarter- to a half-inch of rain across the region, while some mountain and desert areas were forecast to see up to an inch or two, according to the National Weather Service.

The mudslide that hit Cedar Falls Road included parts of a five-year-old burn scar from the El Dorado fire, according to Caltrans.

"The debris flow is from the El Dorado fire, and that mountain peak has an extremely high elevation out of reach for even the most experienced contractors," Caltrans said in a Facebook post. "That fire cause severe terrain damage that has forever changed the scope of that area."

State Route 38 through the San Bernardino Mountains was closed Friday from Valley of the Falls to the bottom of South Fork, according to a California Highway Patrol social media post.

"There is an unknown ETA for the highway to open," the CHP said.

Early Friday morning, a group of about 10 people in six or seven cars were stranded on Highway 38 near Jenks Lake.

"Though cut off by debris in both directions, the group is safe and their needs are being evaluated by emergency crews," according to the post. "Caltrans is working to clear the roadway and restore access."

Near Potato Canyon Road in Oak Glen, another mudslide surrounded nearby homes in mud.

Oak Glen resident Denise Romo told ABC7 that a mudslide rushed down the hillside after the storm hit.

"It kind of sounded like an earthquake was coming," she said. "When I opened my kitchen window I just see the first wave of mud, and it already had trees, mailboxes, a bunch of debris."

Nearby at Oak Glen Road, several cars were stranded by a mudslide.

Casey Geib, general manager of the Oak Glen Steakhouse, told CBS News that he and his co-workers dug their cars out of the debris.

"I thought we would never see mud at this level again," he said. "This time was a lot more aggressive than the last."

While the storms are expected to fizzle out through the weekend, forecasts show that there's the potential for another round of tropical weather next week, but it's too early to tell what will materialize.

Long-range forecasts published this week predict that Southern California could remain in an above-average rainfall pattern for the next week, but it likely won't last. Precipitation outlooks for the month of October -- which marks the officials start of California's rainy season -- did not show an uptick in rainfall.

Mudslides trap drivers, 2-year-old missing in floodwaters as storm batters SoCal