Cyclones

Question 1

What is a tropical cyclone?

Answer 1

A rotating system of clouds and storms that form, and develop over tropical or subtropical waters

Question 2

When is a tropical cyclone known as a hurricane?

Answer 2

Once its winds exceeds 118 km/h

Question 3

Where are hurricanes commonly?

Answer 3

Used in North Atlantic and on the pacific coast of the USA

Question 4

Where are cyclones commonly?

Answer 4

Used in the Indian and South Pacific Ocean

Question 5

Where are typhoons commonly?

Answer 5

Used in the Western North Pacific

Question 6

In the Northern Eastern Pacific Oceans and Atlantic Ocean what hurricane scale is used?

Answer 6

Saffir-Simpson scale

Question 7

In Western Pacific what scale is used?

Answer 7

Meterological Agency scale is used

Question 8

In Australia what cyclone scale is used?

Answer 8

Australian tropical cyclone intensity scale

Question 9

What 4 main hazards do cyclones cause?

Answer 9

Strong winds
Storm surges
Intense rainfall
Landslides

Question 10

What do strong winds involve?

Answer 10

Able to whip up garden furniture, lift roots, vehicles

They bring down trees, destroy whole buildings

Question 11

What do storm surges involve?

Answer 11

Bring flooding caused by unusually high tides
High tides are even higher than normal during a cyclone due to low air pressure
Sea level is raised due to less weight of air holding it down
High tides extend inland causing coastal flooding

Question 12

What does intense rainfall involve?

Answer 12

With thick dense clouds

Not unusual for 1000 mm of rain to fall in a single storm

Question 13

What do landslides involve?

Answer 13

Landslide is a movement of rock, debris or earth down a slope
Caused when ground is saturated by rain causing it to slump

Question 14

How long to tropical cyclones average across?

Answer 14

650km

Question 15

What are the areas known as where tropical cyclones form?

Answer 15

Source regions

Question 16

What are the three conditions for tropical cyclones to form?

Answer 16

A large, still warm ocean - surface temperature exceeds 26.5 degrees over a long period of time
Strong winds in the troposphere, 10-12km above earth’s surface which is needed to draw warm air up rapidly from ocean surface
A strong force caused by Earth’s rotation called Coriolis force. Tropical cyclones DO NOT form near the equator where Coriolis force is minimal but instead between 5-30 degrees latitude

Question 17

Describe the basic formation of a hurricane/ cyclone

Answer 17

Warm air currents rise from the ocean
Updraughts of air contain water vapour from oceans which condenses and produces cumulonimbus clouds
Coriolis force causes rising of air to spiral around the centre of the tropical cyclone
As tropical cyclone tracks away from its source, it is fed new heat and moisture, enlarging it
Once it reaches land mass it loses energy source from ocean. Air pressure rises as temperature falls,winds drop, rainfall decreases and it decays to become a mere storm

Question 18

Why don’t cyclone form at the equator?

Answer 18

Because the Coriolis force is weaker and minimal as it is on,y 5-30 degrees latitude

Question 19

Why do cyclones form over oceans and decay over land?

Answer 19

Over oceans they have more energy but over land they lose their energy as air pressure rises causing temperature to drop and wind to fall

Question 20

Why is the eye of the storm the calmest part?

Answer 20

There are no clouds so there is no rain

Question 21

Which state did Hurricane Katrina hit?

Answer 21

New Orlean, Lousiana

Question 22

What temperature must the ocean water be for a Tropical cyclone to form?

Answer 22

26.5 degrees Celsius

Question 23

What is vulnerability?

Answer 23

A measure of the extent to which a community or area is likely to be damaged or disrupted by the impact of a hazard

Question 24

What is a risk?

Answer 24

Probability of a hazard event causing harmful consequences

Question 25

What factors affect vulnerability?

Answer 25

Preparation 
Education
Population density
Building design
Time of day
Economy 
Sediment type