Drivers skid and crash as wintery mix grips central US before moving east

Road conditions were deteriorating Saturday in the central U.S. as a winter storm brought a mix of snow, ice and plunging temperatures, with forecasts calling for the dreaded combo to spread eastward in the coming days.

“Winter returned,” declared Bob Oravec, lead forecaster at the National Weather Service in College Park, Maryland.

The polar vortex of ultra-cold air usually stays penned up around the North Pole, spinning like a top. But sometimes it escapes or stretches down to the U.S....