The entire population of the Canadian oil city of Fort McMurray was evacuated as firefighters battled an out-of-control wildfire that was likely to worsen Wednesday.
There were long lines on highways as 80,000 residents fled the blaze and oil sands work camps were pressed into service as emergency shelters.
"Apocalyptic" and "harrowing" scenes on social media showed vehicles facing thick smoke and raging roadside flames amid the largest evacuation in the province of Alberta's history.
"The city is under a complete mandatory evacuation order," Wood Buffalo municipality spokesman Robin Smith told NBC News early Wednesday, adding that an estimated 80,000 people had left the city.
He added that "20,000 have gone north to the oil sands camps that have opened their doors to house evacuees" while "35,000 residents have traveled south ... stopping for shelter in the communities of Anzac, Lac La Biche and Edmonton."
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"[With] the heat from the oncoming smoke and the flames, you could see mini-tornadoes forming near the road," Stuffco added. "It was something out of an apocalyptic movie."
Northern Lights Regional Health Centre, the region's main hospital, said Tuesday night that all 105 patients, 73 of them in acute care units, were safely evacuated and were being transported to other facilities.
Twitter users reported that residents alongside one highway held up signs welcoming displaced citizens into their homes.
Fort McMurray isn't actually a fort — instead, it's a city along the Athabasca River. It was renamed from simply McMurray decades ago to honor its earlier history as a military installation.
Canadian Prime Minister Justin Trudeau tweeted that he was paying close attention to the situation.
My thoughts are with people affected by the fire in Fort McMurray tonight. Stay safe and remember to follow evacuation orders. #ymmfire