A tornado struck South-Central Oklahoma in February 2009, killing at least 8 people and injuring 46 others. Tornadoes are violent rotating columns of air that touch both the ground and a cloud. They can be up to a mile wide with wind speeds over 300 mph, and typically travel a few miles before dissipating. The United States experiences the most tornadoes, especially in the central and southern plains states during spring and summer.

3. + 4971A004 Meady
+ 4971A016 Peggy
+ 4971A018 Vera
+ 4971A026 Charles
+ 4971A042 Sophie

5. + A tornado is a violent, rotating
column of air which is in
contact with both the surface
of the earth and a cloud or, in
rare cases, the base of a
cumulus cloud. Tornadoes
come in many sizes but are
typically in the form of a visible
condensation funnel, whose
narrow end touches the earth
and is often encircled by a
cloud of debris.

6. + Most tornadoes have wind
speeds between 40 mph
(64 km/h) and 110 mph
(177 km/h), are approximately
250 feet (75 m) across, and
travel a few miles (several
kilometers) before dissipating.
Some attain wind speeds of
more than 300 mph
(480 km/h), stretch more than
a mile (1.6 km) across, and stay
on the ground for dozens of
miles (more than 100 km).

7. + Although tornadoes have been
observed on every continent
except Antarctica, most occur in
the United States. They also
commonly occur in southern
Canada, south-central and
eastern Asia, east-central South
America, Southern Africa,
northwestern and southeast
Europe, western and
southeastern Australia, and
New Zealand

8. When: 10th February in 2009
Where: South-Central Oklahoma
Casualty: At least eight people were killed ,
46 people with injuries
Destruction: The buildings collapse, the
trees fallen down

16. + Strike quickly, little or no warning
+ Appear transparent until dust and debris are
picked up or a cloud forms in the funnel
+ Moves Southwest to Northeast
+ Speed of a tornado is 30 MPH
+ Accompany tropical storms and hurricanes
+ Peak tornado season:
Southern states → March through May
Northern states→ Late spring through early summer

17. + Weather radio, commercial radio or television
newscasts
+ Look for approaching storms
+ Look for the following danger signs:
– Dark, often greenish sky
– Large hail
– A large, dark, low-lying cloud
– Loud roar, similar to a freight train.

19. + Listen to local officials, and emergency
management personnel.
+ Stay away from downed power lines and other
harmful debris.
+ Check on the elderly and your pets.
+ Use a flashlight and not candles to inspect
damage.
+ Check for any gas leaks and turn the valves off
+ Turn off electricity
+ Watch for any loose debris that could fall.
+ Take pictures

22. + America
+ Spring and summer

23. + big plain
+ The Atlantic Ocean
+ The Pacific Ocean
+ The Gulf of Mexico
+ Middle latitude