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

A powerful storm dropping drenching rain on flood-prone Southern California is raising concern among forecasters that it could produce a dangerous, widespread outbreak of tornadoes, damaging winds and fires along with a blizzard as it crosses the entire United States in the coming days.

A cross-country tornado snow blitz threatens 100 million Americans with the ‘most severe’ storm outbreak of the year. ‘Dangerous, damaging and life-threatening’ weather conditions spanning half a million square miles will smash the US into mid-month.