GREGOIRE LAKE - A wildfire ripping through Canada's oil sands region blazed for a seventh day on Sunday as officials warned almost 100,000 people who fled the area that they would not be returning home soon.The fire, which started at 6 p.m. eastern (2200 GMT) last Sunday near the town of Fort McMurray in northern Alberta, spread so quickly that the town's 88,000 inhabitants barely had time to leave. Large parts of the town no longer exist.Officials said that, even though the fire had largely pushed through Fort McMurray and was heading quickly northeast through dry boreal forests, the town was still too dangerous to enter."Within the community itself I expect over the next coming month or two that they're going to be able to get a very good handle on the fire situation," Alberta wildfire prevention chief Chad Morrison told reporters on Saturday.Thousands of evacuees are camped out in nearby towns but stand little chance of returning soon. Provincial officials said displaced people would be better off driving to cities like Calgary, 655 km (410 miles) to the south, where health and social services are better.Some residents are complaining about the lack of news from the town, fire chief Darby Allen said in a video posted online late on Saturday."We know from all the calls that you're getting frustrated because you don't have any information on your homes. We're really working hard on that, it's a complicated process," he said.The inferno looks set to become the costliest natural disaster in Canada's history. One analyst estimated insurance losses could exceed C$9 billion ($7 billion).