Weather Underground is dedicated to all things weather, including how to prepare for severe weather events.

The Center for Disease Control and Prevention provides information on what to do before, during and after a tornado.

The National Severe Storms Laboratory provides a great overview about the science of tornadoes.

From basic explanations to safety checklists, the Red Cross provides a wealth of information.

Ready.gov provides information on how to prepare for tornadoes, explains terminology and lists interesting facts about tornadoes.

FEMA’s detailed and comprehensive booklet about tornadoes is very helpful for the school setting.