As it roared through the Oklahoma City suburb of Moore, packing winds of up to 200 mph, the twister flattened buildings. Searchers continue to look for survivors and those who were killed.

Melissa Block talks to Casey Mongold, owner of Casey's Tire and Auto in Moore, Okla., where a tornado caused widespread destruction on Monday.

Melissa Block talks to Jon Hamilton about the science of tornadoes.

The state straddles Tornado Alley and has had a number of especially strong twisters leave a path of death and destruction in their wake.