Intense storms spawned catastrophic tornadoes and torrential rain in portions of the US Midwest and South, prompting widespread warnings from the National Weather Service (NWS) of “generational” flooding. The storms, which swept from Texas to Michigan, left extensive damage, two deaths, and hundreds of thousands affected by power outages.

A minimum of 19 tornadoes hit on Wednesday, leveling homes and businesses and injuring at least eight. Two weather-related fatalities were reported by officials in Tennessee’s McNairy and Obion counties. Four were injured in Arkansas’ Craighead County, while a church collapse in Kentucky’s Ballard County left four others injured, including one in critical condition.

The NWS reported that this was only the beginning of an extended and potentially record-breaking weather event. Arkansas, Missouri, Tennessee, and Mississippi are all at serious risk of massive flooding, with parts set to get as much as 15 inches (38 cm) of rain by the weekend. The sheer amount of rain could bring rivers to a burst point, resulting in ruinous flooding.

Missouri’s Emergency Management Agency reported significant damage in Nevada, Missouri, where a tornado overturned train cars and downed power poles. Railroad company BNSF confirmed a freight train derailment near Bay, Arkansas, though the cause remains unclear.

On late Wednesday, Kentucky, Tennessee, and Arkansas announced states of emergency. The NWS alerted severe thunderstorms, more tornadoes, big hail, and potentially life-threatening flooding to persist over portions of Arkansas, Missouri, Indiana, Illinois, Ohio, and Texas.

Over 400,000 customers were reported powerless in the areas affected by storms by Thursday morning, PowerOutage.us indicated. As storms shift towards the east, people are being told to stay cautious and be prepared for the worst.