Tornado 12 : A violently rotating column of air in contact with the ground and extending to the thunderstorm base often seen extending from near the wall cloud. It can be a few yards across to a mile wide
A Guide to Developing a Tornado Emergency Plan for Schools (Also includes information for Instruction of Tornado Safety) and Appendix C: General Tornado Safety, Appendix B: Glossary of Weather Terms, and Appendix C: General Tornado Safety, Tornado and Associated Severe Weather Terms, The Michigan Committee for Severe Weather Awareness), Michigan, USA 1999. http://rems.ed.gov/docs/micswa_tornado_em_plan_for _schools.pdf, (ND Emr/ Tornadoes - Amer) {938}
