CHICAGO (AP) -- Aviation officials say more than 500 flights have been canceled at O'Hare and Midway international airports as the season's first snowstorm moves across the Chicago area.

Snow began falling early Thursday evening at O'Hare.

The National Weather Service has issued a winter storm warning for the area. There could be 2 to 6 inches of snow in the Chicago area.

Snow was heavier and travel conditions more treacherous in northwest Illinois. Authorities in some areas were pulling snow plows off the roads and urging people to stay home.

As wind gusts reached up to 60 mph, more than 50,000 customers lost power. ComEd and Ameren Illinois said there may be delays in restoring service because crews are experiencing hazardous road conditions in some parts of the state.