More than 100 million people in the U.S. will be in the path of an intense March storm starting Friday as the sprawling multi-day system threatens fires, blizzards, tornadoes, and flooding as it tracks eastward across the Great Plains.

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.