UPDATE – 3:30 p.m.
Emcon Services completed clearing the snow from the road and Airport Way is open to traffic.
The Greenslide avalanche path on Mount Cartier slid on Thursday, cascading down to Airport Way, destroying trees along the way, covering more than 100 metres of the road in the process and leaving people stuck on the other side in the process.
The avalanche came down the mountain about 15 kilometres south of Revelstoke on May 4 at around 1 p.m., covering Airport Way in what looked like at least six metres of snow.
It came down just south of several residences, next to a sign that warns of avalanche danger. Part of the slide continued towards the Columbia River, while even more snow built up on Airport Way.
Highway workers and RCMP look at the pile of snow and debris covering Airport Way south of Revelstoke after the Greenslide avalanche path slid on Mount Cartier. ~ Photo by Alex Cooper, Revelstoke Review
17 people were on the other side, waiting to get back to town, said Jeremy Weddell, one of the people blocked by the avalanche.
He was driving back from Echo Lake at around 1:30 p.m. when he saw the debris on the road. “It was a lot of debris,” he said.
The people who were stuck grouped together and were flown out by Search & Rescue at around 5 p.m.
Andrew Stever was working nearby when he heard the slide coming down the mountain.He said at first it sounded like logs being knocked over and he thought it might be from someone logging nearby.
The noise went on for 10 minutes. “I kept hearing trees break and it kept getting louder and louder,” he said.
Stever watched as the avalanche hit the road and moved across it. He said a second slide came down on top of it, depositing even more debris.
Photo: The Greenslide avalanche path descends from the top of Mount Cartier to the valley 2,000 metre below. ~ Photo by Alex Cooper, Revelstoke Review
Gabriel Nava-Lander, the operations manager for highway contractor Emcon Services, told the Review it could take at least three days to clear the mass of snow and debris from the road.
First, they needed to send an avalanche technician up in a helicopter to determine if it was safe to get to work.
“I think it’s bigger than the last one,” he said, referring to the 2014 slide that buried the road eight metres high. “There’s more debris on the other side.”
The Greenslide avalanche path is one of the biggest in southern B.C. and descends more than 2,000 vertical metres from the top of Mount Cartier to the Columbia River.
Val Vizotsky, the lead avalanche technician for the Ministry of Transportation, said it was a class four avalanche, meaning it was capable of destroying small buildings. He said the crown of the avalanche was 800 metres wide and two to three metres deep and left a 75 metre wide deposit on the road that was up to 15 metres deep.
He said it wasn’t as big as the 2014 avalanche. “This one went 30 metres past the road and the one in 2014 went right to the river so it was considerably bigger,” he said. “On the road it’s similar.”
Photo: The start zone of the avalanche shows the fracture line stretching across the top of Mount Cartier and the slide stripping the snowpack down to bare rock. ~ Photo by Alex Cooper, Revelstoke Review
The avalanche occurred on a sunny day following a mostly rainy stretch that likely overloaded the snowpack. The warm temperatures and strong sun weakened the snowpack, sending it down the mountain.
“It’s been winter in the alpine until now,” said Vizotsky.
Karl Klassen with Avalanche Canada posted a blog about this and other big avalanches yesterday, saying the conditions that led to the avalanche could start spreading. Avalanches also hit the road yesterday along Highway 99 east of Pemberton and Highway 93 in Banff National Park.
“These events are a good reminder that just because there’s no snow or steep terrain where you are standing doesn’t mean there’s no avalanche hazard. Given the winter we’ve just experienced and the late spring, I suspect this might be just the preliminary warning shot across the bow,” he wrote. “It will take an extended spell of warmer days and cool nights to promote the repeated melting and re-freezing cycles it will take to stabilize this condition. And we’ll need to see the upper elevation snowpack to melt much farther back before the valley bottom threat is gone. So I’m pretty sure these kinds of events will continue to occur for the next few weeks.”