Cyclones

Cyclones

What do hurricanes have to do with the Swedish chef from the Muppets?

Yorn desh born, Bork, Bork, Bork!

It needs the right ingredients to form!

Warm sea temperatures

needed for cyclones!

Causes

(what makes it happen)

Characteristics

(what things go on in cyclones)

Consequences

(what are the problems caused)

Strong winds (150-200kph)

Buildings blown down

Warm ocean waters (above 25°C)

Descending air forming calm eye

Large waves onto shore

Thunderstorms

Low-lying areas flooded

Low pressure with rising air

Large cumulonimbus clouds

Tropical latitudes

Extremely heavy rainfall

Anti-clockwise rotation in Northern hemisphere

1. Ground heated in summer

Low Low

SUN

2. Hot air rises (think of convectional rainfall)

3. Hot air moves out and cools down

Towards Northern hemisphere (India)

Towards Equator

4. An area of low pressure is created

5. Air from around the system is sucked in, causing ‘spinning’ winds

6. Cool air is pulled in to balance the pressure,

causing the ‘eye’ – calm conditions

7. Cooled air returns to the system

Why does the system rotate?

• Rotation is anti-clockwise in the Northern hemisphere, opposite in the Southern hemisphere

• Coriolis force – the winds are moving straight, but because the Earth is rotating and moves underneath it, it appears to be deflected

• The paths of hurricanes are not usually straight and are unpredictable

Primary effects

(immediate)

Secondary effects

(later)

Primary effects

(immediate)

Secondary effects

(later)

• Flooding of villages and farmland•Loss of houses, animals and crops• People drowned• Communication links like roads and telephone wires, broken• Contaminated drinking water

• Rescue services couldn’t get to the area so people died due to lack of food, clean water etc• Crops destroyed so people starved• Contaminated water spread diseases e.g. cholera• No crops = no income so people poor• Trauma from loss of family members