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.

A severe weather outbreak is expected on Saturday in Alabama, according to the National Weather Service. NOAA’s Storm Prediction Center has added a rarely-used Level 4 out of 5 risk for parts of central and south Alabama for Saturday. The rest of the state is not out of the woods either, and will have a Level 3 risk.

Over the next week, tens of millions of Americans will be at risk of severe weather as a colossal storm marches across the country, threatening hurricane-force winds, major flooding, blizzard conditions and a possible tornado outbreak.