Every major route between the Lower Mainland of British Columbia, where Canada's third largest city of Vancouver is, and the interior of the province has been cut by washouts, flooding or landslides following record-breaking rain across southern British Columbia between Saturday and Monday. The body of a woman was recovered from one of the mudslides late Monday.

“Torrential rains have led to terrible flooding that has disrupted the lives and taken lives of people across B.C. I want people to know that the federal government has been engaging with the local authorities,” Canadian Prime Minister Justin Trudeau said in Washington. “We're sending resources like the Canadian Armed Forces to support people but also we'll be there for the cleanup and the rebuilding after impacts of these extreme weather events.”

The federal government said it is sending the air force to assist with evacuations and to support supply lines.

Military helicopters already helped evacuate about 300 people from one highway where people were trapped in their cars Sunday night following a mudslide,

“We expect to confirm even more fatalities in the coming days,” British Columbia Premier John Horgan said.

Horgan called it a once in a 500 year event. He said the state of emergency will include travel restrictions so the transport of essential goods medical and emergency services will reach the communities that need them. He asked people not to hoard goods.

“These are very challenging times. I've been at this dais for two years now talking about challenging times we have faced — unprecedented challenges with public health, wildfires, heat domes and now debilitating floods that we have never seen before,” Horgan said.

Horgan said over the past six months there have been drought conditions in Merritt, where the river was at its lowest point in living memory and where people had to be evacuated because of wildfires in temperatures that were unprecedented. And now, he said, much of the community is under water.

The weather events are all connected and can be attributed to climate change, said John Clague, a professor in the Earth Sciences Department at Simon Fraser University.

“Scientists are now saying these particular events, they're becoming more frequent, exacerbated or ramped up by climate change,” he said.

The record temperatures in the summer set the stage for the wildfires, said Clague. The fires burned the ground in a way that prevents water from seeping into the soil. He said that resulted in the water from the torrential rains pouring more quickly into steams and rivers, causing floods.

The total number of people and vehicles unaccounted for had not yet been confirmed near the town of Lillooet. Investigators had received reports of two other people who were missing but added that other motorists might have been buried in a slide on Highway 99.

Elsewhere in the province, Abbotsford Mayor Henry Braun said residents of the low-lying Sumas Prairie area south of the city face a significant risk to life and must get out immediately.

An evacuation order was issued for about 1,000 properties Tuesday as flooding linked to a severe weekend rainstorm pushed up water levels in the area which is home to many large dairy farms and other agricultural and livestock operations.

Braun said in a news briefing Wednesday that conditions were dire overnight because a key pumping station was in danger of being overwhelmed. The station was the only thing keeping water from the nearby Fraser River from engulfing most of the Sumas Prairie flats, he said.

“Right now, things are holding steady,” Braun said of the situation at the Barrowtown Pump Station. Crews spent Tuesday night sandbagging around the station.

“I'm feeling much better today than last night,” he said, although he cautioned the danger has not passed and river levels, which have dropped two meters since the storm ended, must drop further before flood gates can be opened to allow even more water to escape.?