Tropical storms hazards Flashcards
What is a tropical storm?
A powerful low-pressure weather system that forms in tropical regions.
Describe the spatial distribution of tropical storms.
-Tropical storms are mostly clustered between the tropics of Cancer and Capricorn, at least 5 degrees north away from the equator.
- In North America and East Asia, there is a high frequency of tropical storms.
- In Africa there are very few tropical storms.
Describe the temporal distribution of tropical storms.
In the Gulf of Mexico (the Caribbean Sea) the worst hurricanes occur during the summer months of August, September and October.
What are the conditions needed to create tropical storms?
- Ocean temperature
- Ocean moisture, latent heat and depth
- Coriolis effect - Earth’s spin
- Atmospheric instability
- Winds
Why are ocean temperatures important in the creation of tropical storms?
A 27 degrees celsius water body provides a continuous source of heat so rising air currents can be maintained.
Why is ocean moisture important in the creation of tropical storms?
The required moisture for the formation of tropical storm to exist is gained through the evaporation of the ocean surface.
Why is latent heat important in the creation of tropical storms?
As the warm air rises, cools and condenses latent heat is released which adds energy to the storm.
Why is the ocean depth important in the creation of tropical storms?
The ocean depth must be at least 70m deep to provide a constant evaporation.
What is the coriolis effect?
The influence of the earth’s rotation on its surface.
Why is the coriolis effect (the earth’s spin) important in the creations of tropical storms?
At the equator, a circular air flow is prevented from developing since the coriolis effect increases with distance from the equator. This means that tropical storms don’t form at the equator.
Why is atmospheric instability (ITCZ) important in the creation of tropical storms?
Tropical storms are most likely to form in regions of intense atmospheric instability.
When does an Intertropical Convergence Zone (ITCZ) form?
When two hadley cells converge to form low pressure on the ground.
Why is wind important in the creation of tropical storms?
A light wind shear (uniform wind direction at all levels blowing)m allows the storm to intensify and grow in height.
How does a tropical storm form?
- Water evaporates from the ocean surface and comes into contact with a mass of cold air
- Clouds form when the water vapour condenses
- A column of low pressure develops at the centre
- Winds form around the column
- As pressure in the central column weakens, the speed of the wind around it increases.
What are the three main hazards of tropical storms?
- High winds
- Heavy rainfall
- Storm surge
