Dam in Chilcotin River will be overtaken by water within hours: B.C. officials

Water is expected to start flowing over a landslide-created dam in the Chilcotin River Sunday night or early Monday morning, according to an update from officials.

Water is expected to start flowing over a landslide-created dam in the Chilcotin River Sunday night or early Monday morning, according to an update from officials.

The Ministry of Emergency Management issued an information bulletin with the updated timeline, while repeating its plea for people to avoid the river between Hanceville and the confluence of the Fraser River.

“People are also advised to stay away from the banks of the Fraser River. Planning continues to address potential impacts of debris as it relates to public safety,” the statement says.

“Risks to public safety include the potential for further landslides upstream of the natural dam and downstream of the dam once water begins to flow past it.”

Since July 30, minimal water has seeped through the massive obstruction – which is estimated at 30 metres deep, 1,000 metres long and 600 metres wide – and water levels behind the dam have been steadily rising by about 18 centimetres per hour.

However, modelling shows that the water is not likely to suddenly burst through the dam, which provincial officials have said would have been the worst-case scenario.

Officials say the best—and most likely—scenario is that it will take 12 to 24 hours for the water to move past the blockage. That would result in water levels below typical spring flooding on the Fraser River, but flows would still exceed freshet peaks on the Chilcotin.