EARTHSC 2GG3 Lecture : Earth Science - Lecture 23 Notes.docx
31 Oct 2013
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Document Summary
A tornado that contains several vortices rotating around, inside of and as part of the main vortex. Visible when: tornado is first forming, condensation and debris are balanced enough so that sub-vortices are apparent without being obscured. Occur in groups of 2-5 at once (6 or 7 is uncommon) Usually last less than a minute each. Responsible for most cases where narrow arcs of extreme destruction lie right next to weak damage within tornado paths. Usually form from weak thunderstorms or rapidly growing cumulus clouds. Usually less intense and cause far less damage. A tornado-like rotating column of smoke and/or fire during the wildfire. Winds associated with firewhirls have been estimated at over 100mph. Fujita scale (f-scale) devised to classify severity of tornadoes based on internal wind speeds and damage produced: f0 causes minimal damage, f5 blows away strong frame homes, f-scale damage chart and photographs correspond to wind speeds.
