More than 4,000 flights were canceled in the US on Saturday ahead of a monster winter storm that has already cut power to more than 160,000 electricity customers as far west as Texas, and threatened to paralyze eastern states with heavy snowfall, Reuters reported. 

Forecasters said snow, sleet and freezing rain, accompanied by dangerously frigid temperatures, would sweep the eastern two-thirds of the nation on Sunday and into next week.

Calling the storms "historic," President Donald Trump on Saturday approved federal emergency disaster declarations in South Carolina, Virginia, Tennessee, Georgia, North Carolina, Maryland, Arkansas, Kentucky, Louisiana, Mississippi, Indiana, and West Virginia, according to Reuters.