Science Tornadoes: Why there? Why now? (+video)

A devastating tornado that ripped through south-central states of Arkansas, Oklahoma and Iowa Sunday has killed at least 18. Why weather conditions in spring are conducive for tornadoes in the central and south US, say experts.

By , Staff writer

Angie Davis/Reuters

On Sunday, powerful tornadoes ripped through Arkansas, Oklahoma, and Iowa, leaving at least 18 dead.