Introduction One of the most violent natural disaster

is the 300 MPH whirling wind.A tornado appears as a rotating, funnel-

shaped cloud that extends from a thunderstorm to the ground with

whirling winds that can reach 300 miles per hour.

tOrNaDo

Definition:A tornado is a violently rotating column of air that is in contact with both the surface of the earth and a cumulonimbus cloud (thundercloud)

Most tornadoes have - wind speeds less than 110 miles per hour (177 km/h), - height 250 feet (76 m) across and - travel a few miles (several kilometers) before dispelling.

The most extreme tornadoes can attain wind speeds of more than 300 miles per hour (483 km/h), stretch more than two miles (3.2 km) across, and stay on the ground for dozens of miles (more than 100 km)

How a tornado is formed?Most tornadoes form from thunderstorms. You need warm, moist air from the Gulf of Mexico and cool, dry air from Canada. When these two air masses meet, they create instability in the atmosphere. A change in wind direction and an increase in wind speed with increasing height creates an invisible, horizontal spinning effect in the lower atmosphere. Rising air within the updraft tilts the rotating air from horizontal to vertical. An area of rotation, 2-6 miles wide, now extends through much of the storm. Most strong and violent tornadoes form within this area of strong rotation.

Put it in Graphic…here is a tornado formation

Levelling a tornado

• Tornadoes can be categorized as –Weak (wind speed less than 110 mph)–Strong (wind speed between 110-200 mph)–Violent (wind speed more than 200 mph)

What causes a tornado?

• Various climate and environmental trends– For example• Instability in the atmosphere such as …– an increase in the sea surface temperature of a

source region (e.g. Gulf of Mexico and Mediterranean Sea) increases atmospheric moisture content.– Increased moisture can fuel an increase in severe

weather and tornado activity, particularly in the cool season.

Impact of a tornado

Environment• Destroys trees, plants,

farms• Kill animals (disrupt food

chain)• Water contamination• Fires may occur after a

tornado due to damaged power lines and gas leaks.

Human• Deaths

– kill an average of 60-80 people per year

• Destroy building – Homes, hospitals, schools

• Property damage– Vehicles, facilities such as

electricity plant, clean water tanks, daily life equipment