Tropical Storms

Question 1

What is a tropical storm?

Answer 1

A large scale, atmospheric disturbance.

Question 2

What are the characteristics/conditions needed to form?

Answer 2

• 60m water depth
• 26.5°C water temp
• Over 74mph wind
• Bring excessive rainfall, and have a storm surge

Question 3

Describe the formation

Question 4

What is the effect of wind shear?

Answer 4

Can tilt or even break it apart to prevent its formation.

Question 5

What is the distribution of tropical storms?

Answer 5

• 5-30 degrees NS of equator
• Not on equator as no Coriolis effect
• Lots in SE Asia

Question 6

How are tropical storms measured?

Answer 6

Saffir-Simpson scale, with wind speed being the triggering factor which defines the category. Doesn’t take into account rainfall or damage.

Question 7

What are the hazards associated?

Answer 7

• Strong winds; 75mph+, they do damage by tearing off roofs, breaking windows, damage communication networks.
• Coastal and river flooding; flash flooding can occur from heavy rainfall, often more than 200mm in just a few hours.
• Landslides; intense rainfall increases pore pressure and adds weight.
• Storm surges; responsible for 90% of all deaths from tropical storms. Caused by sea levels rising due to intensely low pressure and shallowing water. Waves are pushed towards shore at speed.

Question 8

Give some factors which affect people’s vulnerability to storm hazards.

Answer 8

• Intensity of storm
• Distance from sea
• Physical geography of area
• Preparations by community
• Warnings
• Speed of movement of the storm, how long it stays over an area

Question 9

How is climate change affecting tropical storms?

Answer 9

Becoming more intense, by about 10%. Rainfall increasing in them, making storm surges higher due to rising sea levels.