Debris from a landslide is shown from the air near Testalinden Creek, just south of Oliver, B.C., on Sunday. (Daniel Hayduk/Canadian Press)

It is still not clear what caused a mudslide on Sunday afternoon that destroyed as many as five homes in a B.C. community, but all the residents survived without any deaths or injuries.

A wall of mud, water and debris tore down a mountainside at about 2:20 p.m. PT near Testalinden Creek, just south of Oliver, B.C., RCMP said.

"It happened very quickly and we are very fortunate that nobody was hurt," said Allan Patton, regional director with the District of Okanagan-Similkameen.

Patton, who has surveyed the area, said officials are still assessing the damage, but he said at least four — possibly five — large homes are beyond repair.

"You can tell by just looking at them right away that the walls are caved in, the roofs are all keeled over and they're toast, they're finished," he said.

About 50 people were forced to leave the area and it's not clear when they will be allowed to return to their homes.

The slide hit Highway 97, the main highway through the Okanagan, at Road 14. It left a wall of mud about 3.5 metres high over the stretch of highway about 300 metres wide.

Heavy rains may be cause

Ministry of Environment officials are assessing the situation and looking into the exact cause of the slide. More information may be released at a news conference scheduled for Monday morning, said officials.

"They have to make sure that the area is secure before they can open any roads up," Patton said, noting that the electrical system and water system were damaged as well.

The area has been hit with heavy rain of late, but it remains unclear exactly what may have caused the slide.

The Oliver Mayor Pat Hampson said it appeared water may have built up in a mountain creek before flooding down.

"It looks as if there may have been a blockage way up in the mountains and the possibility of a build up of water behind logs or log jams or even a build up of rocks — we won't know that for quite awhile — and that broke free and it came running down the creek as a debris flow," said Hampson.

Patton said the flood of water may have caused a high-mountain lake to breach its banks, eroding the road that was holding it back.

"That lake rose above a road level up there and eroded the road and then the whole lake just drained right away, all the way down the mountainside, and some slides happened along the way, just adding debris and rocks and mud and all that kind of stuff. It happened really quickly," said Patton.

Homes destroyed

"When that big rush of water came down it just went over its banks right away and took out the houses, and lots of orchard land and cabins and machinery sheds," Patton said.

Oliver city councillor Rick Machail heard the landslide as it happened and he spoke with some of the families that were affected.

"It was just like a freight train coming down from the hills and it was just a wall of mud," he said.

"One person I talked to said she had some of the Mexican workers that help us in the orchards here, and they were in a shed and she quickly ran and grabbed them and said, "Let's run!"

"They ran and part of that shed actually got destroyed on the south side and mud went into the shed. It's like a moonscape, like lava coming down or something — just a wall of mud. It's incredible to see up close."

Susan Von Pander wasn't home when the creek running near her home became a raging torrent, damaging her house and nearly destroying a neighbouring property.

"The Yenches — they were our neighbours above us. If their house hadn't been there, our house would have been gone. It diverted the water. It was horrible. I felt horrible for them as well," said Von Pander.

"The whole mountainside had fallen down; it was horrible, just horrible," she said, adding that she can't get back into her house.

Freelance photographer Daniel Hayduk said some homes were ripped off their foundations.