Tornadoes struck the Midwest over the weekend, hitting cities and towns in Kansas and Missouri. And one snarl on I-70 left experts concerned about tornado safety.

A relentless stretch of severe weather that left 28 dead and unleashed destruction across the central and eastern United States in recent days isn’t letting up yet, with millions more in the path of dangerous weather this week.

"A maturing central U.S. storm system is expected to produce another round of dangerous severe weather and instances of flash flooding today," the National Weather Service warned Monday. The forecast discussion added that "from a broader perspective," locally heavy rain was forecast to reach from the northern Plains to Texas.

Experts say planning before a tornado threatens is key for staying safe. Weather radios, basements and bicycle helmets can all help save lives.

On Friday, drivers on I-170 near St. Louis were stuck in storms after others parked under an overpass—an unsafe move experts warn can cause backups and danger.

"Severe thunderstorms capable of all severe hazards remain possible this evening across portions of the central and southern Plains," a forecast from the National Weather Service's Storm Prediction Center (SPC) said. "Several strong to intense tornadoes are possible," it added.

St. Louisans, particularly in north city, were facing the daunting task of recovery from the storm's devastation, many without power and few resources.