US flooding forces entire city to evacuate as rivers reach historic highs

National Guard troops went door-to-door on Friday to evacuate a farming city north of Seattle as severe flooding in western Washington state put levees at risk.

Days of torrential rain have swelled rivers to record or near-record levels, as flooding has stranded families on rooftops, washed over bridges and ripped homes from their foundations. Burlington, a city of nearly 10,000 residents near Puget Sound - a large inlet of the Pacific Ocean in northwestern Washington - was placed under a full evacuation order with people told to leave immediately and move to higher ground.

The Skagit River, a major waterway that flows from the Cascade Mountains through the Skagit Valley before emptying into Puget Sound, surged to a record high of nearly 38ft (11.6m) at Mount Vernon, about 10 miles south of Burlington. "We haven't seen flooding like this ever," said Karina Shagren, a spokesperson for the state's emergency management division, adding that there had been no reports of injuries or missing individuals so far.

National Guard troops and sheriff's deputies were going door to assist with the evacuations. Some responders were seen paddling stranded Burlington residents to safety in inflatable river rafts through the muddy floodwaters.

Later on Friday, the evacuation order was lifted for part of the city, Burlington police department spokesperson Michael Lumpkin said. However, while water levels appeared to ease a little, Mr Lumpkin said "it's definitely not an all-clear".

Read more from Sky News:Heavy rain and floods set to hit parts of UKKing reveals 'good news' in his battle with cancer The intense rainfall was driven by an atmospheric river, a massive stream of moisture drawn from the ocean and carried inland over the Pacific Northwest earlier in the week. Although rainfall has begun to ease, the National Weather Service has issued a flash-flood warning for the Skagit River basin all the way downstream to its mouth at Puget Sound.

The swollen waters could put enough strain on levees to cause them to fail, the weather service noted. "Extensive flooding of streets, homes and farmland will be possible" if levees and dikes give way, it said.

The Burlington-Mount Vernon area in Skagit County continues to be the hardest-hit area, facing extensive flooding from days of heavy rainfall stretching from northern Oregon through western Washington and into British Columbia. National Guard troops were also dispatched to deliver food and check on stranded residents in a number of communities cut off by flooding in adjacent Snohomish County, south of Skagit County.

The flooding washed out or forced the closure of dozens of roads throughout the region, including most of the Canadian highways leading to the port city of Vancouver in British Columbia. Parts of northern Idaho and western Montana have also been impacted..