Landslide blocking B.C. river could give way within 24 to 48 hours

A massive amount of debris from a landslide damming the Chilcotin River in British Columbia's central Interior could give way within the next 24 to 48 hours.

Margo Wagner, chair of the Cariboo Regional District, says water building up behind the slide south of the city of Williams Lake could reach a level where it will start flowing over the debris, or it will erode the material, causing it to give way.

Wagner told a news briefing that the riverbed below the slide is dry, and officials aren't certain about the potential downstream impacts when the dam is breached.

But she says it's clear there would be "a mass of water" coming down the Chilcotin, which flows south into the Fraser River.

Evacuation orders span 107 square kilometres along the Chilcotin, with the regional officials saying the slide poses an "immediate danger to life and safety."

The district says 60 properties are covered by the orders, including 12 homes with an estimated 13 residents.

Wagner says the slide is "massive," with material piled 30 metres high and stretching 600 metres in length, completely blocking the flow of the Chilcotin.

"As the water continues to flow and builds up behind that landslide, the pressure increases, but we do not have definitive time of when that will let go."

A statement from the provincial government says the sudden release of the blockage could cause "rapid rises" in water levels along the Chilcotin and the Fraser River all the way to Hope, about 150 kilometres east of Vancouver.

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