A sweeping storm system moving across the U.S. threatens to bring tornadoes, blizzards and possibly wildfires to different regions of the country.

Over the next week, tens of millions of Americans will be at risk of severe weather as a colossal storm marches across the country, threatening hurricane-force winds, major flooding, blizzard conditions and a possible tornado outbreak.

A potent storm system is expected to pour heavy rain on western states later this week before rumbling into the central United States, where it could spawn tornadoes

A potent storm system is expected to pour heavy rain on western states later this week before rumbling into the central United States.