'Extremely unsafe': BC officials warn of dangers around Fraser, Chilcotin River banks as water tops dam

(UPDATE: Aug. 5 @ 3:30 pm) - The B.C. government says it's "extremely unsafe" to be near the banks of the Chilcotin and Fraser rivers both upstream and downstream from a massive landslide after water started flowing through the slide early Monday.

Emergency Management Minister Bowinn Ma said Monday that the water breaching the dam caused by the slide will cause river bank instability, although the chances of a worst-case scenario are "decreasing."

Ma says people should stay away and off the waters as officials monitor the flow downstream of the slide, which may impact the Farewell Canyon Bridge, about 22 kilometres downstream.

Evacuation alerts and orders along the rivers are not just about residential properties, she said.

"It is also about people recreating on the water or along the waterways," Ma said at a briefing Monday. "We need people to leave those areas, to not put their boats down, to not go down to take a look at the water, to not engage in recreation activities anywhere along the Chilcotin River or the Fraser River right now."

Officials said about 15 properties in the Cariboo and Thomson River Regional Districts are on evacuation order or alert.

Connie Chapman with the province's water management branch said the "pulse" of water from the dam breach will likely erode river banks, and carry debris from the slide.

She said the water started flowing through the debris slide, cutting about a 15 metre channel through the dam, and then began widening with water flows increasing by the hour.

She said some places along the rivers will see higher than spring runoff levels and cause the rivers to swell downstream in the coming days.

Chapman said officials will be monitoring debris in the "big pulse of water" now flowing downstream from the site of the slide.

An emergency alert issued by the province Monday said anyone along the banks of the rivers from Hanceville to the Fraser River, down to the Gang Ranch Road Bridge south of Williams Lake, must leave. Flooding and moving debris pose "a threat to human life," the alert said.

Images posted online by the province, and aerial footage over the slide site shared by Nathan Cullen, B.C.'s water and resource minister, show water getting through the massive slide.

The provincial government estimates the landslide that dammed the river is 1,000 metres long, 600 metres wide and 30 metres deep.

The Thompson-Nicola Regional District said all private properties within 300 metres of the banks of the Fraser River are on evacuation alert, including four addressed properties adjacent to the river, including two properties on Big Bar Road, one on Empire Valley-Big Bar Road, and another on Watson Bar Road.

The Tsilhqot'in National Government said in a social media post that people should also avoid river banks that were submerged by the lake that formed behind the slide. Tsilhqot'in Chief Joe Alphonse said the water backed up enough to start carving a path through the slide debris, and impacts on upcoming salmon runs remain his nation's biggest concern.

B.C. officials issued an evacuation order Sunday night for an area just north of where the Chilcotin River meets the Fraser River because of the danger of flooding caused by the landslide. In a news release late Sunday, officials with the Cariboo Regional District told residents to leave "immediately" and said people who chose to stay did so at their own risk. The evacuation order covered 3.5 square kilometres.

The massive landslide last week at Farwell Canyon located about 22 kilometres south of Williams Lake dammed the Chilcotin River and created a lake about 11 kilometres long behind the slide.

The Tsilhqot'in First Nation said that as of Sunday morning the slide was holding back 61 million cubic metres of water, equalling "24,400 Olympic swimming pools."

(UPDATE: Aug. 5 @ 11:30 am) - The Tsilhqot'in National Government says water has begun flowing overtop the landslide that dammed British Columbia's Chilcotin River.

The First Nation says on social media that people should avoid river banks that were submerged by the lake that formed behind the slide.

Images posted online today by the province and aerial footage over the slide site shared by Nathan Cullen, BC's water and resource minister, show water getting through the massive slide.

Tsilqot'in Chief Joe Alphonse says the water has backed up enough to start carving a path through the slide debris, and impacts on upcoming salmon runs remain his nation's biggest concern.

BC officials issued an evacuation order for an area just north of where the Chilcotin River meets the Fraser River because of the danger of flooding caused by the landslide.

In a news release late Sunday, officials with the Cariboo Regional District told residents to leave "immediately" and that people who choose to stay do so at their own risk. The evacuation order covers 3.5 square kilometres.

The massive landslide last week at Farwell Canyon located about 22 kilometres south of Williams Lake dammed the Chilcotin River and created a lake about 11 kilometres long behind the slide.

The Tsilhqot'in First Nation said that as of Sunday morning, the slide was holding back 61 million cubic meters of water, equalling "24,400 Olympic swimming pools."

(UPDATE: Aug. 5 @ 10:00 am) -Authorities in British Columbia have issued an evacuation order for an area just north of where the Chilcotin River meets the Fraser River because of the danger of flooding caused by a landslide.

In a news release Sunday night, officials with the Cariboo Regional District told residents to leave "immediately" and that people who choose to stay do so at their own risk. The evacuation order covers 3.5 square kilometres.

A massive landslide last week at Farwell Canyon located about 22 kilometres south of Williams Lake dammed the Chilcotin River and created a lake about 11 kilometres long behind the slide.

Sean Leslie, spokesman for the ministry of water, land and resource stewardship, said in a statement Monday that water trapped behind the natural dam has not yet reached the top, although levels rose overnight. Leslie said that the height of the trapped water is similar to what is witnessed during the spring thaw but is expected to move more quickly and with greater force.

Experts expect water will reach the top of the natural dam and start flowing into the riverbed in the next several hours, he added.

The Tsilhqot'in First Nation said in a social media post that as of Sunday morning, the slide was holding back 61 million cubic meters of water, equalling "24,400 Olympic swimming pools."

British Columbia's Emergency Management Department said on Sunday that water was expected to start moving over the top of the massive landslide site within hours.

The department urged people to stay away from the Chilcotin and Fraser rivers because of the threat from the landslide.

The River Forecast Centre issued flood warnings for the Chilcotin River upstream and downstream of the landslide near Farwell Canyon.

A flood watch is in effect for the Fraser River from the Chilcotin River confluence downstream to Hope, B.C.

The department is scheduled to provide an update on the landslide later on Monday.

(Original story: Aug. 5 @ 7:45 am) -British Columbia's emergency management ministry says water is expected to start moving over the top of the massive landslide site currently blocking the Chilcotin River within hours.

The ministry says in a statement area modelling suggests water is expected to start moving over the top of the landslide site late Sunday or early Monday and enter the riverbed below the slide area.

The statement says minimal seepage from the slide site is being observed, but the water level behind the dammed area continues to increase at about 18 centimetres per hour.

The ministry statement says the most likely scenario to occur in the coming hours involves the trapped water moving through the slide area over 12 to 24 hours and resulting in flows downstream at the Fraser River resembling typical spring runoff, but higher peak water flows along the Chilcotin River.

The ministry says a worst-case scenario could involve a rapid draining of the slide site, which could result in a 21-metre rise of the Chilcotin River near the Farwell Canyon Bridge, but typical spring freshet flows downstream along the Fraser River.

A massive landslide Wednesday at Farwell Canyon located about 22 kilometres south of Williams Lake dammed the Chilcotin River and created a lake about 11 kilometres long behind the slide.

The ministry says people are urged to keep out of the Chilcotin River valley between Hanceville and the confluence of Fraser River

It says an evacuation order issued by the Cariboo Regional District remains in place.

People are also advised to stay away from the banks of the Fraser River.

The ministry 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.

The ministry says it is preparing for all possible outcomes since modelling does not provide guarantees.

Emergency Management Minister Bowinn Ma said at a news conference on Saturday that dangers remain and people should heed evacuation orders and alerts and stay away from the river areas.

The ministry says it has set up a new web portal for Chilcotin River landslide information, visit: https://gov.bc.ca/landslide.