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.

On Thursday, the storm was bringing heavy snow and strong winds to the Sierra Nevada and heavy rainfall over parts of coastal southern California.

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.