Snow from an avalanche is seen near B.C.’s Coquihalla Highway in this March 23, 2012, photo.Meagan Hancock/the Globe and Mail
Helicopter crews dropped bags of explosives on an avalanche that has closed the Coquihalla Highway on Friday, but couldn't make the province's No. 1 east-west trade corridor safe enough for the public to use, says the transportation minister.
Highway 5 was closed Thursday, following a slide that was described by one search-and-rescue official as being "massive" and powerful enough to destroy houses.
Transportation Minister Todd Stone said it will remain closed at least until Saturday afternoon, after about three metres of snow dropped on a weaker layer of snow along the highway's corridor during the past nine days, and despite "bombing missions" by three helicopter crews.
He said snow is sitting precariously on some of the mountain peaks above the highway.
"We were able to get three helicopters in the air, and what the helicopters do is they fly over the avalanche zone," he said. "They effectively drop bags of explosives, they refer to it as bombing missions.
"The explosives explode on impact, and what that does is it dislodges the additional snow that is sitting precariously above these avalanche zones, the goal being to get as much of that snow to come down as quickly as possible."
Stone said the crews ran out of daylight Friday but there's still about three to four hours of "bombing work" to do. He said once the work is done the contractor can move into the avalanche zone on the highway and begin to remove the snow.
Meantime, maintenance crews will be working through the night on either side of the avalanche zone, clearing as much snow as they can, he said.
If visibility is good when day breaks Saturday, the helicopters can get back in the air and get the excess snow down, he said.
"I would hope that if Mother Nature co-operates we would hope to have the Coquihalla open by tomorrow afternoon."
He said Mother Nature dealt the highway a pretty huge blow, noting that of the nine metres of snow, about one metre fell within a single day.
"It is unprecedented to have three metres of snow in nine days," he said. "We have no record of an accumulation of that amount in that short period of time in the entire 27 years of the Coquihalla Highway."
The closure marks the third time on one week that the highway has been shut down.
The ministry closed the Coquihalla for about four hours Feb. 15 for avalanche control work.
The highway reopened but the ministry was forced to close it again on Tuesday after an avalanche struck near the summit.
On Thursday, a massive slide hit the highway.
Doug Fraser of Chilliwack Search and Rescue called it a Class 4 avalanche, "massive," and powerful enough to destroy houses.