tropical cyclones Flashcards
What type of pressure system is a tropical cyclone?
An intense, rotating low-pressure system (below 950mb).
How long do tropical cyclones typically last?
Between 7 and 14 days.
Name four key features of tropical cyclones.
Heavy rainfall, wind speeds over 119 km/h, high waves, and storm surges.
What is the typical diameter range of a tropical cyclone?
Between 100 and 1000 km.
What is found at the centre (eye) of a tropical cyclone?
Calm conditions, descending cold air, low pressure, light winds, no clouds or rain.
Where are the most destructive winds found in a cyclone?
: In the eyewall — with spiralling storm clouds, torrential rain, and low temperatures.
What are conditions like at the edge of a tropical cyclone?
Lighter winds, scattered clouds, less intense rain, and rising temperatures.
What is the Saffir-Simpson scale based on?
Wind speed.
At what category is a tropical cyclone considered ‘major’?
Category 3 (winds of 111–129 mph or 178–208 km/h).
What are the wind speeds of a Category 5 tropical cyclone?
Over 157 mph (252 km/h).
What causes a low-pressure system to form during cyclone development?
Rapid rising of warm, moist air.
What happens after warm air rises in a tropical cyclone?
Air rushes in from surrounding areas to replace it, creating a continuous updraft.
How does rising air help power a tropical cyclone?
It cools and condenses, releasing latent heat energy.
What causes the spinning motion in tropical cyclones?
The Coriolis effect.
What forms the calm centre of the storm?
Sinking air in the middle creates a cloudless, calm eye.
What happens when a cyclone moves over land or cold water?
It loses its warm moisture supply and begins to weaken.
What are tropical cyclones called in the Western Pacific?
Typhoons.
What are they called in the Atlantic and Caribbean?
Hurricanes.
What are they called in the Indian Ocean?
Cyclones.
Where do tropical cyclones typically form?
Over warm oceans between 5° and 30° latitude north and south of the equator.
Why do tropical cyclones initially track westward?
Because of easterly trade winds near the equator.
: Why do cyclones change direction and move eastward later?
They enter areas with westerly winds in the mid-latitudes.
: When do most tropical cyclones occur in the Northern Hemisphere?
Between June and November.
When is cyclone season in the Southern Hemisphere?
Between November and April.
