New rounds of severe thunderstorms and life-threatening, potentially catastrophic, flooding risks are brewing in the central and eastern United States Tuesday, putting more than 50 million people at risk this week.

Two people died Saturday night in an Oklahoma City suburb after floodwaters swept their truck into a creek, police said. One of the deceased was 12 years old.

After severe thunderstorms moved across Oklahoma overnight, more severe weather is expected Tuesday. Here's what we know.