Fire crews are working around the clock to dig fuel breaks, spread fire retardant and drop water from the air in emergency efforts to stop a vast wildfire from destroying the capital city of Canada’s Northwest Territories (NWT). Teams used backhoes and bulldozers to carve out huge 100m x 15,000m fuel breaks in the surrounding forests, removing trees and brush in hopes of stopping the 1,670 sq km (644 sq mile) blaze from reaching Yellowknife. Officials in the city of 20,000 told reporters they were also considering ignition operations – in which fires are purposely set to starve the wildfire of fuel. Mike Westwick, NWT’s fire information officer, said small-scale ignition had helped in a second fire near the settlement of Ingraham Trail, just east of Yellowknife. “We’re heading into a couple of critical days during the management of this fire,” he said. But hopes that the weather could help the firefighting effort were dashed, as just one millimetre of rain fell on Thursday. Officials implored Yellowknife residents to heed the evacuation order for the city. “We expect to see north-west to west-north-west winds over the next two days, and those are winds that will trend both of those fires in directions we don’t want,” Westwick said. But with evacuation orders in place across the region, some resident reported difficulties in staying on top of the fast-changing events: communications have been hampered by rumours, patchy cellphone reception and a Facebook ban on sharing news links. Canada is enduring its worst wildfire season, with more than 1,000 active fires burning across the country, including 236 in the Northwest Territories. Fires in the territory have burned more than 2m hectares of land, and more than half of the region’s population is under evacuation orders. Four fires are burning in the North Slave region, the most densely populated area of the territory. Yellowknife officials warned residents not to evacuate by boat on the Great Slave Lake as the fire is unpredictable and air quality is expected to worsen. On the other side of the lake, a new evacuation order was placed on Kakisa, a small Dene First Nation community. Other Dene communities – N’dilo, Dettah and Ingraham Trail – are also under orders to leave immediately. “Our territory has never experienced anything like this in terms of wildfire,” Westwick told the Guardian. Thousands of evacuees from across NWT have fled to Alberta, to the south. Evacuee reception centres have been set up as far south as Calgary, nearly 2,000km from Yellowknife. Stephanie Mercredi left her home in Fort Smith, on the border of NWT and Alberta, when its evacuation order was enforced nearly a week ago. Mercredi, who is Dene, travelled with seven of her family members including four children. They first tried to evacuate to the village of Hay River, three hours away, only to turn around when that community was also given an evacuation order. They eventually reached an evacuation centre on a reserve near High Level, Alberta. “They were super warm and welcoming, and after being on the road 14 hours, it was just what we needed,” she said. Over recent days, long lines of traffic have clogged Highway 3 – the only road out of Yellowknife – as officials warned residents to get out while they still could. Yellowknife’s mayor, Rebecca Alty, said driving conditions were safe for now, but added that she couldn’t promise the road would stay open as fire and thick smoke drift closer. Meanwhile, airlift operations have been ongoing since Wednesday. Authorities said 10 planes carrying about 1,500 people took off from Yellowknife on Thursday, and another 22 flights are expected on Friday, said Jennifer Young, a communication officer with the territory. Flights may continue into Saturday if the weather, planes and crew hold out. Facebook’s recent ban on sharing news links on the social media platform – as well as poor cellular reception in some areas – has left evacuees in some areas relying on word-of-mouth and the radio to get up-to-the-minute information. Citizens and news organisations in Canada are barred from posting news links to Facebook and Instagram after the technology giant disabled access last month due to a row with the federal government over legislation that would force internet giants to pay news publishers. Katrina Nokleby, a provincial elected official and geological engineer in Yellowknife, said the social media platform could not be trusted as a source of reliable information. She encouraged people to instead read the local network Cabin Radio’s liveblog to get the latest facts. Speaking from Yellowknife on Thursday about 5pm local time, Nokleby said that though she had seen a number of people still in town while helping to distribute medical supplies, it appeared many had already left. A few hours later, she packed up some things – and several cats – and joined her fellow Yellowknifers on the road.