Residents in holding pattern as B.C. landslide inches toward homes
FORT ST. JOHN — Residents of a small community in northern B.C. are struggling without answers about when they can return home, as scientists try to determine if a nearby slow-moving landslide will take a catastrophic turn.
Gordon Pardy of Old Fort said it feels as if he’s in a pressure cooker, as he prepares to start a new job on Monday knowing that his home of 25 years could be buried at any moment or very slowly swept away.
“Our lives are upside down. My daughter, my wife and myself — we have two dogs and a bird and we’re all living in a hotel room right now,” he said. “It’s emotional.”
The slumping hillside was first reported to authorities on Sept. 30 and has prompted the evacuation of the entire community of Old Fort and two islands next to the community in the Peace River.
An evacuation alert has also been issued for the outskirts of nearby Fort St. John, meaning anyone in that area should be prepared to leave at a moment’s notice.
Although the only road in and out of Old Fort has buckled, Pardy has been returning to check on his home and others using an ATV.
He said that he looked in on his house on Thursday, possibly for the last time.
The Peace River Regional District posted a notice that day saying anyone found disobeying an evacuation order could face fines of up to $10,000 or jail time.
The slide is surreal because you can’t see it moving even when you know it is, Pardy said.
“It’s like when you look at the hands of a clock and you don’t see them moving, but you turn around and come back after five minutes and it’s moved five points over.”
Some residents in the area recall the 1973 Attachie slide about 40 kilometres away, he said. In that case, the earth slipped at a rapid speed, damming the Peace River.
Marten Geertsema, a research geomorphologist studying the Old Fort slide for the B.C. Forests and Lands Ministry, said it doesn’t appear to have too much in common with the Attachie slide.
He said scientists with the ministry and Westrek Geotechnical Services are monitoring the slide using laser light technology and helicopter surveys to figure out exactly what triggered it.
There are two slides underway, he said.
Debris from the main slide has blocked a channel in the Peace River near Old Fort and started to encroach on a nearby island. A large compression crack west of there has dropped five to six metres into the earth, which could further destabilize the westerly slide, Geertsema said.
The westerly slide is carrying a house and a lagoon that remains full of water with it, he said.
“It’s like having a pile of mashed potatoes on your plate and pushing it with a fork. You can have all sorts of little things on top of the mashed potatoes and they don’t deform, but they’re still moving,” he said.
Even if the slide doesn’t suddenly slip, he said a slow-moving slide can still sweep away a village.
“It can either hit a house and bulldoze them or sometimes, when the failure plane or rupture surface is really deep, it can carry them away,” he said.
Peter Bobrowsky, a senior research scientist in landslides based at the Pacific Geosciences Centre in Sidney, said landslides are especially common in the Peace Region because of the history of glaciers forming and melting over tens of thousands of years.
That process creates three main layers of sediment that interact in a way that makes them vulnerable to sliding.
The least porous layer is where trouble occurs because it can get heavy with water when it rains, he said.
There have been hundreds of thousands of landslides in the Peace Region in the past 10,000 years, ranging from the size of a wheelbarrow to tens of millions of cubic metres, he said.
Hopefully, the landslide will stop before any real damage occurs to the homes, he said. But they can also start again and it’s hard to predict how long the break will be.
“It can be minutes, hours, days, years, decades,” he said.
“One of the advantages of a catastrophic failure is it happens, then they monitor it for a while to make sure there isn’t going to be anything else, and then they get to work cleaning it up, buttressing the slope,” he said.