The destruction left behind by a torrent of debris that washed out Mabel Lake Road on Friday, May 2, 2014. The investigation in the cause of a breach that sent millions of gallons of water pouring out of Dale Lake is proving a challenge given the extensive destruction.

(CHARLOTTE HELSTON / iNFOnews.ca)

VERNON – While the exact cause of the massive landslide that wiped out a section of Mabel Lake Road has yet to be pinpointed, investigators have a much better idea of what happened.

On Friday, May 2, millions of gallons of water from Dale Lake swept along Cooke Creek in the Kingfisher area east of Enderby dredging up all kinds of material from mud to trees.

Then a buildup of debris behind a structure formed partially by a forestry road gave way.

Ron Baker, the community and protective services manager with the Regional District of the North Okanagan, says the "structure" also includes what could be a beaver dam which had also plugged two culverts under the road.

"What we don’t know is what gave rise to the breach," Baker says.

Investigators, including geotechnical experts, from the Ministry of Forests, Lands and Natural Resource Operations are leading the probe into that question.

The ministry is expected to release a preliminary report soon, although Baker isn’t optimistic there will be much more investigation after that.

“It’s a case of the province investigating the province,” he says. Forestry roads are a provincial responsiblity.

A statement from the ministry points out “the investigation is challenging as the culverts were washed away by the debris torrent.”

Baker says a lot of water was released from Dale Lake when the breach occured. The rough estimate is between 4.5 to 9-million gallons. He says it’s impossible to provide an exact number.

Meanwhile, he says there’s no way to determine exactly the ongoing risk from the material that scoured and degraded the stream channel, adding “it could take years for the debris to clear away.”

Another fallout from the slide is all the debris that will make it’s way into, or already has made its way into, Mara Lake and the Shuswap River.

“It’s going to cause problems for boaters and shoreline property owners for some time," Baker says.

As for Mabel Lake Road, it should re-paved and fully re-opened by the middle of next week.

Image Credit: Vernon Search and Rescue

To contact the reporter for this story, email Howard Alexander at halexander@infotelnews.ca or call 250-491-0331. To contact the editor, email mjones@infotelnews.ca or call 250-718-2724.

- This story was corrected at 9:26 a.m., on Sunday, May 11, 2014 to change the name of Mabel Lake to Mara Lake.

News from © iNFOnews, 2014