A large mudslide has shut part of the Trans-Canada Highway in southern British Columbia, after debris blocked four lanes of highway and a railway line. At least one vehicle and a CN freight train were caught in the slide, but no one was seriously hurt.

The slide occurred at around 10:30 a.m. not far from the Herrling Island exit, about 140 kilometres east of Vancouver in the Fraser Valley.

The slide, which left a pile of debris 40 metres wide and 15 metres deep in parts, surged over the four-lane highway and trapped 20 CN rail cars.

Witness Tabitha Lindsay told CTV News she looked up and saw streams of water sliding off the mountain.

"I drove a little bit further ahead and there was this big, big stream, it looked like a river was coming down, and it was just really muddy," Lindsay said. "My car just started sliding across the road."

Emergency crews from Hope, about 30 kilometres to the east, responded to the incident. However, their search for more potential victims was hampered by unstable debris. Only late in the afternoon did emergency crews deem it safe to begin searching for vehicles that may have been trapped.

"We walked the area as best we could to determine if there were any further vehicles under the slide, but we were unable to locate any," said Sgt. Peter Thiessen, adding heavy equipment would also be brought in to aid the search.

Lynn Orstad, from the Fraser Valley Regional District, told The Canadian Press that at least one car was hit during the slide. She added that the car rolled over twice, but the female driver was left with only a bruised knee.

The driver walked into a nearby truck stop and spoke to employee Cindy Mackin.

"She was shaking, literally," Mackin said the woman.

"She said she seen the trees coming down and she slammed on her brakes and then she seen it basically happen right in front of her."

Orstad said the woman's injuries were minor compared to the nature of the accident. The woman's car rolled twice, Orstad said.

Meanwhile, CN said that no employees were injured.

"There were no injuries, and there was no derailment as a result," said CN spokesperson Kelli Svendsen, adding that the train was heading west.

"(Police) are just on scene and they're assessing the incident and how to address it."

The RCMP has said no homes were affected by the mudslide.

The Ministry of Transportation said it isn't clear when the highway will be opened, but ministry staff called it a "serious" slide.

Detours were in place late Wednesday to move traffic around the site.

Late Wednesday, water and mud were still sliding off the mountain, and engineers from the province as well as other experts were flying over the scene to assess the safety situation.

Kim Edmunds, of the Ministry of Transportation, said the incident may be blamed on the weather, specifically "the heavy rain cycles" that have hit the area.

"It's been a long, long wet season this spring," Edmunds said. "Just a combination of that long season was the right circumstance for it."

However, Environment Canada meteorologist David Jones said weather may not have played a role in the slide, considering the area had no more than 30 millimetres of rain over the previous 24 hours.

"I would be looking in other directions," he said. "Because I looked at the radar and even then it didn't look like there was much in the way of heavy rain showers that were persistent over a particular area."

With a report from CTV's Michele Brunoro and files from The Canadian Press