When Nature Strikes: Tornadoes
Perhaps the most terrifying natural hazards are tornadoes. "Sudden," "huge," "devastating," "unpredictable" - these only partly describe why people fear these storms. Unlike hurricanes, which can affect large regions over many hours or days, tornadoes are relatively small and short-lived. But some can last for hours and leave widespread death and destruction in miles-long paths. Damage can seem to be random: houses on one side of a street may be ripped apart, yet those on the other side are unaffected. Most are single events, but some occur in clusters that include dozens of separate events, such as the "Super-Outbreak of 1974".
A tornado is, basically, a violently rotating column of air (vortex) descending from thunder-storms. Enhanced Fujita Scale". Like many weather events, thunderstorms which may spawn tornadoes follow a characteristic life cycle. There are also "tornado look-alikes" which people may confuse with actual tornadoes.
This "When Nature Strikes" video explains that scientists still do not understand why some storms produce the funnel clouds of tornadoes, but similar systems do not. Numerous research projects seek to understand why mesocyclones in supercells produce the most destructive and deadly tornadoes.
"What Could You See as a Tornado Approaches?" classroom activity
"When Nature Strikes" is produced by NBC Learn in partnership with the National Science Foundation.
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