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.