Emergency officials say flash floods are “imminent” and could happen within 24 or 48 hours after a landslide blocked the Chilcotin River in British Columbia’s Cariboo region.
On Wednesday, the Tŝilhqot’in National Government said a slide of soil and debris about 300 metres wide fully blocked the river at Nagwentled, also known as Farwell Canyon, around 285 kilometres north of Vancouver.
“Flooding is building up above the dam created by the landslide, so it’s like a lake,” Cariboo Regional District chair Margo Wagner said at a virtual news conference Thursday.
“There is a high risk of a flash flood downstream if the river breaches that landslide — which it is expected to do eventually.”
B.C.’s River Forecast Centre issued a flood warning for the Chilcotin River upstream of the landslide. It’s also issued a flood watch for the Fraser River, from where it meets the Chilcotin River downstream to Hope, B.C.
Wagner told reporters water could either rise up over the landslide, or water could cause a fissure in the earthen barrier, causing it to give way.
“We don’t know exactly when this landslide is going to give way,” she said. “There would be a mass of water coming down.”
She said many trees and debris from a wildfire in the region is also being held behind the landslide.
The Tŝilhqot’in National Government issued an evacuation order for the area Wednesday morning.
The Cariboo Regional District also issued two evacuation orders for a dozen homes, affecting 13 residents, due to “immediate risk of flooding.”
The orders cover 60 parcels of land along the river, an area totalling about 106 square kilometres.
A map on the district’s website shows the area stretches from the Big Creek Bridge, about 50 kilometres east to where the Chilcotin and Fraser rivers meet.
According to DriveBC, Highway 97 is closed in both directions between North Beach and Callan roads due to the landslide. Evacuation orders recommend residents head north to Highway 20, then east into Williams Lake, B.C.
Province assessing damage
In a news release, B.C.’s Water, Land and Resource Stewardship Ministry said personnel are assessing the landslide on the ground.
The B.C. Wildfire Service is helping assess the situation with aircraft, and has also dispatched several helicopters to help with search and rescue in the area.
“The province is prepared to take additional actions to keep people and communities safe in the event of flooding, such as deploying sandbags, sandbag machines, gabions and Tiger Dams,” a Ministry of Emergency Management and Climate Readiness spokesperson said in the release.
Man rescued
One man was rescued after being trapped by the slide.
In an email to CBC news Thursday, B.C. Emergency Health Services said the man was rescued and taken to the Wiliams Lake Airport by helicopter, and from there to hospital.
Paramedics said no other injuries linked to the landslide have been reported.