A major winter storm is set to spread heavy snow and damaging ice across a large portion of the United States over the coming days. Dangerously cold temperatures will only worsen the storm and increase its danger.

Almost 4,000 flights were canceled in the U.S. on Saturday ahead of a monster winter storm that has already cut power to thousands of utility customers as far west as Texas, and threatened to paralyze...

More than 150 million Americans were under some form ‍of weather emergency notices from the National Weather ​Service.