Terrible Tornadoes

Recently we have seen the destructive power of yet another type of natural hazard, the tornado in both the USA and New Zealand. April 2011, was one of the most active months for Tornadoes in US history with over 180 reported causing over 305 deaths.

This short news clip outlines some of the events:

The video below displays someones brave effort filming the Tuscaloosa Tornado.

This year the USA has witnessed an incredible amount of tornadoes, many of which rated highly on the Enhanced Fujita scale which rates tornadoes according to their intensity based on the level of damage.

The Enhanced Fujita (EF) scale is based on one invented by Ted Fujita in 1971, and has been used since 2007 to measure the strength of tornadoes in the USA. The scale ranges from 0-5. It was first applied to tornadoes in eastern Florida measuring EF3. The first EF5 tornado was at Greensburg, Kansas, on 4th May 2007.


Wind Speed

(mph, km/h)



65-85, 105-137

None or minor; branches broken; shallow rooted trees pushed over; damage to roofs and gutters.


86-110, 138-177

Moderate: roofs badly damaged; mobile homes overturned; glass broken; doors ripped off


111-135, 179-217

Considerable; large trees uprooted or broken; roofs torn of; mobile homes destroyed; cars lifted


136-165, 219-266

Severe: trees de-barked; trains overturned; large strong buildings damaged; weak structures blown away.


166-200, 267-322

Extreme: houses leveled; cars thrown about


200+, 322+

Total: strong houses blow away; steel reinforced concrete buildings and high rise buildings badly damaged.

The US has experienced tornado of the following intensity in 2011 so far:

Total: 719

EF0: 215  EF1: 316  EF2: 128  EF3:42  EF4: 15  EF5: 3

If you want to know more about tornadoes:

Animated Guide to Tornadoes: http://news.bbc.co.uk/1/hi/5328524.stm

National Geographic also provide a good overview of tornadoes and some incredible images of tornadoes and their destructive power.

National Geographic Tornadoes: http://environment.nationalgeographic.com/environment/natural-disasters/tornado-profile/

Shapes and sizes of tornadoes: http://www.chaseday.com/tornadoes.htm

From the National Hurricane Center in the USA: http://www.nhc.noaa.gov/HAW2/english/tornadoes.shtml

This entry was posted in hazards, Physical geography, Weather and tagged , , , , . Bookmark the permalink.

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