What could be the worst ice storm in 10 years began Friday in the central U.S., as forecasters warned it will unload freezing rain on a 1,000-mile swath from the central Plains to the mid-Atlantic over the weekend.
The storm is expected to cause downed trees, extensive power outages and make driving dangerous or impossible as roads turn into sheets of ice.
The worst conditions could be centered on portions of northwestern Texas, western Oklahoma and central Kansas, where there is the potential for about an inch of ice to encase the region followed by 30-mph winds, AccuWeather meteorologist Eddie Walker said.
Some of the big cities likely to be hit by the ice include Topeka, Oklahoma City, Kansas City, St. Louis, Indianapolis, Columbus, Pittsburgh and Washington, D.C., AccuWeather said.
Dozens of flights were canceled at airports in St. Louis and Oklahoma City on Friday as freezing rain moved in across the region.
Travel will be hazardous for hundreds of miles along Interstate 35, I-40 and I-70 in the central states, said AccuWeather meteorologist Brett Rossio.
In southern Missouri on Friday morning, some areas already picked up a tenth of an inch of ice on outdoor surfaces, according to Andy Foster, a meteorologist with the National Weather Service.
An ice storm warning, in place through Sunday in many areas, was already in effect for most of Kansas and Missouri and parts of Oklahoma.
Missouri's department of transportation said it could be the worst ice storm in 10 years there and said motorists should avoid travel through Sunday. "Ice is the most difficult storm to fight," said maintenance engineer Becky Allmeroth.
By Saturday, widespread freezing rain and/or sleet will extend from the central and southern Plains into the Ohio Valley and mid-Atlantic states, according to the Weather Channel. The ice storm will continue in the central Plains on Sunday.
In Kansas, up to 1 inch of ice was expected to fall in "multiple rounds" of freezing rain through Monday, making travel extremely hazardous, the weather service in Kansas City warned.
Freezing rain occurs thanks to a "warm air sandwich" in the atmosphere, in which a layer of warm air hovers between cold layers both above and below it. Precipitation that begins as snow at the highest level of cold air melts into rain in the warm air, then refreezes as it falls into the cold layer near the surface.
Missouri Gov. Eric Greitens called a state of emergency Thursday and said the Missouri Transportation Department started pre-treating roads and would continue to do so throughout the storm. Oklahoma Gov. Mary Fallin declared a disaster emergency for all 77 counties in the state in advance of the storm.
The Weather Channel has named the storm Winter Storm Jupiter.