A colossal storm system is rapidly developing across the United States, threatening to unleash a barrage of extreme weather events, including tornadoes, flash flooding, blizzard conditions, and wildfires.

The forecast comes days after an expansive storm similarly trekked across the U.S. last week, unloading snow in the northern Plains and bringing tornadoes and wildfires to the South. At least five storm-related deaths in Nebraska and Mississippi were tied to that storm.

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.