Deadly Missouri Tornado Sparks Severe Weather Threat for Millions.

A tornado struck southeastern Missouri before dawn on Wednesday, killing at least five people in Bollinger County. The twister caused significant destruction in and around the small rural communities of Glen Allen and Grassy. A search and rescue operation is underway that involves multiple agencies. Schools in Little Rock, Arkansas, canceled Wednesday classes because the storms were expected to move through the area during the morning rush. The Storm Prediction Center said up to 40 million people in an area that includes Chicago, Indianapolis, Detroit, and Memphis, Tennessee, were at risk from the storms later Wednesday.