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Ice storm warnings were in effect across much of the nation’s midsection Friday as a wicked winter storm moved through the area and gave it a glazing of ice that was quarter inch thick in some places.

For millions of Americans that means slippery highways, downed trees, lightning strikes and widespread power outages across the heartland, the National Weather Service warned.

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In icy Oklahoma, Gov. Mary Fallin declared a state of emergency in all 77 counties.

Missouri Gov. Eric Greitens did so on Thursday, calling up the National Guard and activating the state’s Emergency Operations Center. State police said it was investigating a fatal traffic accident blamed on the weather south of Crystal City Friday.

And the NFL announced it was moving Sunday's playoff game between the Kansas City Chiefs and Pittsburgh Steelers, which is being played at Arrowhead Stadium in Kansas City, from 1:05 p.m. ET to 8:20 p.m. ET to "provide local authorities more time to clear roads in the area as the weather is expected to improve."

Overnight Friday, the icy conditions were expected to spread across the Ohio Valley and over the Appalachians to the nation’s capital, where preparations are already underway for President-elect Trump’s inauguration next week.

While not in the path of the nasty weather, dozens of flights in and out of Chicago's O'Hare Airport were cancelled Thursday due to icy conditions in the region.

Blame the ice on a combination of moist air from the Gulf of Mexico sliding over the sub-freezing air currently blanketing the Midwest and Northeast, The Weather Channel reported.

Meanwhile in Oregon, Gov. Kate Brown declared a state of emergency after it was buried by snowfall.

"As snow continues to accumulate and local authorities respond to provide core services and clear roadways, all available state resources will be made available to ensure the safety of communities throughout Oregon," Gov. Brown said. “I urge all Oregonians to follow the recommendations of local authorities, and avoid travel."

Eastern Oregon has been hit especially hard. More than two feet fell in Bend as of Wednesday, setting a new record, according to the NWS.