HAZARDS: Storm Hazards Flashcards Preview

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Flashcards in HAZARDS: Storm Hazards Deck (23)
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1

Tropical storms

Large spinning storms with strong winds + torrential rain.

2

What conditions are needed for a tropical storm?

  • Disturbance near the sea-surfcae, eg. low pressure
  • Warm water (above 27oC to at least 50m below surface) = lots of evaporation
  • Convergence of air in lower atmosphere - forces warm air to rise
  • At least 5o from the Equator, as this is where coriolis effect is strong enough

3

What are tropical storms in the Caribbean Sea called?

Hurricanes

4

What are tropical storms in the Bay of Bengal called?

Cyclones

5

What are tropical storms in the China sea called?

Typhoons

6

Why do tropical storms lose strength over land?

Supply of warm, moist air is cut off.

7

What do tropical storms initially do?

Move westwards due to easterly winds in tropics

8

Why do tropical storms move away from the equator?

Due to Coriolis effect.

9

How long do tropical storms usually last?

7-14 days

10

How do tropical storms spin in the northern hemisphere?

Anticlockwise

11

How do tropical storms spin in the southern hemisphere?

Clockwise

12

Describe the structure of a tropical storm:

  • Area of low pressure at centre = eye
  • Rising air spirals around eye in the eyewall, causing strong winds
  • Outflow of moisture-laden air near top = cloud cover extends for a long distance

13

How are storms classified?

Using the Saffir-Simpson Scale, which is based on wind speed.

14

How does the Saffir-Simpson Scale work?

  • Rates storm hazards on a scale from 1-5 (category 5 is the strongest)
  • Estimates how much damage a storm of a given magnitude will do

15

Category 5

Stongest storm hazard.

Winds over 250km/h

16

Category 1

Weakest storm hazard.

Winds of 120-150km/h

17

Describe the frequency of tropical storms:

Around 100 a year.

Northern hemisphere - June to November

Southern hemisphere - November to April

18

Why can the path of a tropical storm be predicted fairly accurately?

Cloud formations can be identified by satellite imagery - shows formation of tropical storm.

Can then be tracked using satellites and models.

 

19

What are some of the forms a storm hazard can take?

High winds

Storm surges

Heavy rain

Flooding

Landslides

20

Storm surge

A large rise in sea level caused by high winds pushing water towards the coast, and by the low pressure of a storm.

21

How can the impact of storm hazards be reduced by prevention?

Cannot be prevented, but can be studied to identify high-risk areas.

Future developments can be planned to avoid these.

 

22

How can the impact of storm hazards be reduced by prepardness

  • Emergency services cna train + prepare for disasters
  • Evacuation routes can be planned 
  • Education

23

How can the impact of storm hazards be reduced by adaptation?

  • Buildings can be designed to withstand storms + floods
  • Flood defences can be built