British Columbia's Coquihalla Highway has again been closed due to what a search-and-rescue official calls a massive avalanche.

The route linking the south coast and southern Interior was closed earlier this week for nearly a day when a small avalanche struck near the highway's summit.

Doug Fraser of Chilliwack Search and Rescue said that a Class 4 avalanche came down on the highway late Thursday, although he didn't know the exact location.

Story continues below advertisement

"It's a massive avalanche ... the power from that would destroy houses," he said.

Fraser said his group and another were on standby, but he hadn't heard of any vehicles being caught in the slide.

The current storm cycle on the highway's corridor has created avalanche conditions not seen since the Coquihalla opened 27 years ago, the ministry said in a news release.

"This is a really unique winter up on the Coquihalla," added Paula Cousins, a ministry spokeswoman. "We've had some just really unique conditions because of the cold temperatures and a really weak basal layer in the snow pack."

Just when the highway will reopen remains unknown, although the ministry's DriveBC website says it has tentatively scheduled avalanche control for Friday morning.

Meantime, detours were available via Highway 1 at Kamloops and Hope, or at Highway 8 in Merritt.

Earlier in the day, the Canadian Avalanche Centre issued a special public warning about the potential for large, destructive avalanches in all B.C. mountain regions, except for the area just north of Vancouver.

Story continues below advertisement

Spokesman Karl Klassen said fresh snow is sitting atop one of the weakest surface layers they've seen in years after an extended dry period in late January and early February.

He said the weakness is currently between one and two metres deep and could result in very big slides.

While the drought has created pent-up demand for powder by recreational backcountry users, Klassen said the weak layer will persist for the foreseeable future.

Everyone in a group venturing into terrain is being urged to carry an avalanche transceiver, probe and shovel and have a good knowledge of rescue skills.

The centre is also recommending backcountry enthusiasts take an avalanche skills training course and check the avalanche bulletin regularly to stay informed of conditions in their area.