CHICAGO (CBS) — An overnight ice storm has left thousands without power and is affecting the morning commute.

Up to a half inch of ice had accumulated at airports in Aurora as well as at Chicago O’Hare and Midway.

The good news: while there might be some minor snow showers or light drizzle in some areas, the precipitation is largely over for northern Illinois. However, a wind advisory will go into effect this afternoon, and gusts of 45 to 50 mph could put even more stress on tree limbs and power lines coated in ice.

With temperatures already above freezing around dawn, some of that ice hopefully will melt before the strong winds arrive.

Meantime, enough snow fell in the northwest suburbs for teams of plows to be called out well before dawn in the hopes of getting roads and expressways cleared in time for the morning rush. In Barrington, for example, roads were completely covered in snow overnight.

Both the South Shore and Metra Electric lines are not running due to ice. For Metra, the Rock Island Line is an alternative. The CTA is also accepting Metra passes.

The CTA also is dealing with its own delays. Green Line trains were running late during the morning rush, due to mechanical problems caused by the icy weather.

As of 10:45 a.m., approximately 7,700 ComEd customers are without power. The areas with the highest outages were in Chicago and the western and southwestern suburbs, including Downers Grove and Joliet.

ComEd said about 400 crews were working to make repairs after the ice storm, and has restored power to more than 40,000 homes and business so far Tuesday.

Roads were slippery, but salt trucks were treating streets and there were no reports of any major accidents as of 5:20 a.m. Police did report several spinouts, as a mix of snow, sleet and rain fell.

Guy Tridgell, with the Illinois Department of Transportation, said traffic on the expressways is moving, but side streets are slick. He cautioned drivers to take extra time.

Some schools, especially those in Northwest Indiana, are closed or opening late. 

As of 10:45 a.m. 296 flights were canceled at O’Hare and 95 were canceled at Midway.