Landslide blocking river in British Columbia could subside in 24 to 48 hours

A massive amount of debris from a landslide that is damming the Chilcotin River in British Columbia’s central interior could disappear within the next 24 to 48 hours.

Margo Wagner, chair of the Cariboo Regional District, says water collecting behind the landslide south of the town of Williams Lake could reach levels where it could flow over the debris or erode the material, causing it to fail.

Wagner told a news conference that the riverbed below the landslide is dry and that authorities are unsure what the potential consequences downstream would be if the dam were to fail.

But she says it is clear that there will be “a lot of water” flowing down the Chilcotin, which flows south into the Fraser River.

The evacuation orders cover a 40-square-mile (107-square-kilometer) area along the Chilcotin River. Regional officials say the landslide poses an “imminent threat to life and safety.”

According to the district, 60 buildings are subject to the measures, including 12 houses with an estimated 13 residents.

Wagner says the landslide is “massive,” with material piling up 100 feet high and 2,000 feet long, completely blocking the flow of the Chilcotin.

“As the water continues to flow and builds up behind the landslide, the pressure will increase. But we don’t know exactly when that will happen.”

According to a statement from the provincial government, the sudden lifting of the blockade could lead to “rapid rises” in water levels along the Chilcotin and Fraser Rivers all the way to Hope, about 150 kilometres east of Vancouver.

This report by The Canadian Press was first published August 1, 2024.