Do tornadoes follow well-worn tracks? Where do the deadliest twisters hit? Will climate change make such storms worse? Monday's devastating tornado in Oklahoma raises some questions for which scientists have ready answers, and others that could puzzle them for years to come.
A fourth-grader at a school that took a direct hit from Monday's deadly tornado in Moore, Okla., described the heroic actions of a teacher who saved his life and others by covering several students with her body to shield them from the storm.