New Delhi, Jan. 24 -- Freezing rain fell in parts of Texas on Friday as a huge, dayslong winter storm began a trek that threatened to bring snow, sleet, ice, bone-chilling temperatures and extensive power outages to about half the U.S. population. Forecasters warned that catastrophic damage, especially in areas pounded by ice, could rival that of a hurricane.

Schools in Chicago and other Midwestern cities called off classes, airlines canceled thousands of weekend flights, churches moved Sunday services online and the Grand Ole Opry in Nashville, Tennessee, decided to hold its Saturday night radio performance without fans. Carnival parades in Louisiana were canceled or rescheduled.

At least 182 million people were under watches or warnin...