Hurricane-force winds, blizzard conditions, heavy snowfall — and a “bomb cyclone” on the West Coast: Those are the dire predictions of weather forecasters, who are warning Thanksgiving travelers to be cautious and prepare for delays as two powerful back-to-back storms hit the western and central U.S. this week.

The National Weather Service’s U.S. forecast map is draped in alarming shades of pink, purple and red, reflecting winter storm warnings that are in effect from California to Michigan.