A. Tornadoes

Question 1

What is a tornado?

Answer 1

A tornado is a violently rotating column of air that descends from a thunderstorm (and connects with the ground level)

Question 2

What are the characteristics of a tornado?

Answer 2

• Rapidly rotating vortex of air
• Most violent of atmospheric storms (more intense than a hurricane)
• Smaller in size and short lived (1 minute to 7 hours)
• High damage in a small area (travel from 100m to 100km)
• Narrow path of destruction (2m to 2km wide)

Question 3

What are the hazards of a tornado?

Answer 3

• High wind speeds - typically 70-318 mph
• They have a strong lifting force - like a giant vacuum cleaner!
• Rapid change in pressure when they occur

Question 4

How many tornadoes does the USA receive each year?

Answer 4

• The USA recieves about 1000 tornadoes each year (75% of the world’s tornadoes)

Question 5

Where else can tornadoes form outside the USA?

Answer 5

• Tornadoes can also form in Europe, but they are often known as “twisters” and are far less powerful
• Other locations include Uruguay and parts of Argentina, as well as South Africa, Australia and New Zealand
• In Asia, they form in parts of north India, the coast of China, South Korea, Japan and the Philippines

Question 6

When are tornadoes most commonly found?

Answer 6

• Form ahead of an advancing cold front, or where air masses at different temperatures meet
• Mainly form during supercell thunderstorms (1/1000 chance)
• Can form where there is strong solar heating
• Require wind shear

Question 7

How does a tornado form?

Answer 7

Winds at different altitudes blow at different speeds, creating wind shear, forming a horizontally rotating cylinder of air at the boundary between the two winds.

This rotating column of air then gets caught in the updraft, causing the spin to tighten and speed up creating a funnel cloud

The rain and hail in a thunderstorm create a downdraft and cause the funnel to head downwards, becoming a tornado when it makes contact with the ground.

Question 8

In which seasons are tornadoes more common? Why?

Answer 8

Tornadoes are more common during spring and early summer.

• This is because there are greater temperature differences between the temperature of the warm and cold air at this time of year

Question 9

During which times of day are tornadoes more common? Why?

Answer 9

Tornadoes are more common during afternoon and early evening.

• This is because the land has a higher temperature, having been heated by insolation throughout the day, increasing convectional uplift.

Question 10

Why are tornadoes often found in Tornado Alley?

Answer 10

• The Great Plains in the USA are very flat and open.
• The sun can heat up the fields quickly causing air to rise rapidly
• Tornadoes can move over the flat land very easily
• Cool, dry air from Canada and the Rockies meets warm, moist air from the Gulf of Mexico

Question 11

When did the Rolling Fork tornado occur?
In which state?

Answer 11

March 24 2023
Mississippi

Question 12

What were the primary hazards of the 2023 Rolling Fork tornado?

Answer 12

• Strong winds up to 170 miles (274km) per hour = a 4 on the Enhanced Fujita Scale
• Many homes in Rolling Fork were trailers = easily picked up by the tornado and thrown as debris causing great damage

Question 13

What were the secondary hazards of the 2023 Rolling Fork tornado?

Answer 13

A second tornado touched down near Black Hawk, Mississippi, 56 miles / 90km north of Rolling Fork.

This tornado was a 3 on the Enhanced Fujita Scale, and also caused significant damage in its 29 mile / 47km long path with maximum winds of 150 miles / 241km per hour

Question 14

What were the primary impacts of the 2023 Rolling Fork tornado?

Answer 14

• Strong winds destroyed 313 buildings and damaged over 1000. Many residents were living in mobile homes, turned over by the tornado. The nearby Silver City was also damaged
• 21 people killed in the tornado, which travelled 59 miles with a width of 3/4 of a mile in 1h10 min
• Rolling Fork’s water tower was destroyed, leaving thousands with minimal access to services

Question 15

What were the secondary impacts of the 2023 Rolling Fork tornado?

Answer 15

• Long economic recovery expected due to Rolling Fork’s lower economic status - mobile homes and buildings of poor quality were completely destroyed
• Federal Emergency Management Aid has approved over $5 million in individual assistance to survivors and $6 million to Sharkey County fot the removal of debris
• Sharkey County is the poorest county in Mississippi, and 1/5 of residents in Rolling Fork lie below the poverty line.