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A wintry storm caked America's centre with a thick layer of ice, blacking out more than 600,000 homes and businesses, and more icy weather was on the way.
At least 17 deaths in Oklahoma and Missouri were blamed on the conditions, with 15 of them killed on slick highways.
A state of emergency was declared for Oklahoma, where the sound of ice-heavy branches snapping echoed through Oklahoma City.
"You can hear them falling everywhere," Lonnie Compton said as he shovelled ice off his driveway.
The National Weather Service posted ice and winter storm warnings for parts of Missouri, Kansas, Nebraska, Iowa and Illinois. Missouri declared an emergency on Monday and put the National Guard on alert.
Oklahoma utilities said 500,000 customers were blacked out as power lines snapped under the weight of ice and falling tree branches, the biggest power outage in state history, and utilities in Missouri said more than 100,000 homes and business had no power there.
- AP
