PGCE Developing Subject Knowledge |
KS4 Geography
KS4 Geography - Weather Hazards and Climate Change
National curriculum for geography aims to ensure that all pupils understand the causes, consequences of and responses to extreme weather conditions and natural weather hazards.
Teaching ideas
a) What do you already know about extreme weather events and hazards?
Work individually to create a mind map to show what you already know about extreme weather events. Listed below are some example questions to be considered: 1) What is the definition of an extreme weather event? 2) How does an extreme weather event differ from normal day weather? 3) List some examples of extreme weather events. 4) Does the UK experience any of those examples? b) Watch the following video and get the students to compare the two examples, in order to determine whether the consequences and impacts of a tropical storm change between developed and developing countries. After watching the video discuss as a class. |
Extreme Weather Events and Hazards
What is an extreme weather event?
Extreme weather is when a weather event is significantly different from the average of usual weather pattern. These events are usually intense periods of weather, such as a flash flood. What is a weather hazard? A weather hazard is an extreme weather event which threatens the lives and safety of people and property. What are examples of extreme weather events and hazards?
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Tropical cyclones
What is a tropical cyclone?
A tropical cyclone is an extreme weather event that results in heavy rainfall, strong winds and other weather hazards such as, mudslides and floods. Tropical cyclones usually form between approximately 5 and 30 degrees latitude.
There are a number of different terms and names used to describe tropical cyclones depending upon its speed. When the winds of the cyclone reach 39mph it is classified as a Tropical Storm, and if the winds reach 74mph it is classified as a hurricane in the Atlantic and north-east Pacific and a Typhoon in the north-west Pacific.
Due to the conditions required for a tropical cyclone to form, there is a set tropical cyclone season. For the North Atlantic this season is June to November, and for the North Pacific this season is from January to March. Although tropical cyclones are one of the most dangerous natural hazards they are essential features of the earth's atmosphere as they transfer heat and energy from the equator to the cooler regions.
How does a tropical cyclone form?
A tropical cyclone requires a lot of heat in order to form, which is why they usually form over the tropical oceans. The heat from the tropical oceans causes the air above it to rise rapidly. As water is evaporating quickly from the warm ocean surface is causes the rising air to contain high amounts of water vapor. The rising air starts to spin, in a clockwise direction in the northern hemisphere and anti-clockwise in the southern hemisphere, due to the Coriolis effect. The center of the storm, the eye, is relatively calm. As the air rises it cools, condenses and forms towering thunderstorm clouds (cumulonimbus clouds). The rapidly rising air creates an area of intense low pressure, which the sucks in the surrounding air, creating very strong winds. This is then classified as a tropical cyclone, as it is an area of low pressure, high strong winds and heavy rainfall. However as the tropical cyclone moves over the land it loses it energy source from the high ocean temperatures and begins to fade and slow down.
Click on the following video to watch the formation of a tropical cyclone.
What are the conditions required for a tropical cyclone to form?
Several conditions are required for a tropical cyclone to form:
Why is a tropical cyclone classed as a natural weather hazard?
A tropical cyclone is classed as a natural weather hazard as it is an extreme weather event of heavy and intense rainfall with strong high winds and strong storm surges, that puts both people lives and safety and property at risk.
What are the impacts and consequences created by tropical cyclones?
Extreme weather events like tropical cyclones can have severe impacts and consequences on the environment and communities. The intense winds created by the tropical cyclone are strong enough to destroy buildings, whole communities and communication networks. Not only are the communities and buildings at risk from the high winds, they are also at a high risk of flooding due to the intense rainfall and storm surges. One of the main consequences created by the tropical cyclones is the economic impact, with many people being left homeless and many business being destroyed.
The impacts and consequences of a tropical cyclone are different between the developed and the developing world, as the developed world have more financial, educational and economical resources to help deal with the consequences, and to help improve the prevention of these consequences.
What are the responses to a tropical cyclone?
There are both short and long term responses to tropical cyclones, with short term responses occurring before the hazard and immediately after the tropical cyclone. The short term responses often vary from place to place depending upon their knowledge of the impending hazard, and their accessibility to evacuation plans and resources. Long term responses are often focused on repairing the damage created by the tropical cyclone, and increasing their protection and prevention methods in case of future cyclones.
The responses to a tropical cyclone vary considerably between both locations and events, as each tropical cyclone is different and each location experiences different consequences, so it is easier to understand the responses by focusing on a case study.
The case study we will use is Hurricane Katrina New Orleans, 2005.
Examples of their short-term responses are:
Examples of their long-term responses are:
Is there a geographical distribution of tropical cyclones?
Due to the physical conditions required from a tropical cyclone to form, there is a distinct geographical distribution of tropical cyclones. They are distributed around the equator at 5-30 degrees. Although tropical cyclones occur in both the northern and southern hemisphere, they are more frequent and common within the northern hemisphere. Tropical cyclones are most frequently seen to hit land and create severe impacts within the USA and Asia, in the other regions they are frequently located over the seas and oceans, reducing the consequences and impacts. Below is a map which highlights the distribution of tropical cyclones.
When the winds of a tropical cyclone reach 74mph and above it becomes classified by a number of different names depending on its location. In the Atlantic and north-east Pacific ocean they are known as hurricanes, the north-west Pacific ocean refers to them as typhoons, the south-west Pacific ocean and south-east Indian ocean classifies them as severe tropical cyclones, the north Indian ocean refers to them as severe cyclonic storms, and the south-west Indian ocean classifies them as tropical cyclones.
A tropical cyclone is an extreme weather event that results in heavy rainfall, strong winds and other weather hazards such as, mudslides and floods. Tropical cyclones usually form between approximately 5 and 30 degrees latitude.
There are a number of different terms and names used to describe tropical cyclones depending upon its speed. When the winds of the cyclone reach 39mph it is classified as a Tropical Storm, and if the winds reach 74mph it is classified as a hurricane in the Atlantic and north-east Pacific and a Typhoon in the north-west Pacific.
Due to the conditions required for a tropical cyclone to form, there is a set tropical cyclone season. For the North Atlantic this season is June to November, and for the North Pacific this season is from January to March. Although tropical cyclones are one of the most dangerous natural hazards they are essential features of the earth's atmosphere as they transfer heat and energy from the equator to the cooler regions.
How does a tropical cyclone form?
A tropical cyclone requires a lot of heat in order to form, which is why they usually form over the tropical oceans. The heat from the tropical oceans causes the air above it to rise rapidly. As water is evaporating quickly from the warm ocean surface is causes the rising air to contain high amounts of water vapor. The rising air starts to spin, in a clockwise direction in the northern hemisphere and anti-clockwise in the southern hemisphere, due to the Coriolis effect. The center of the storm, the eye, is relatively calm. As the air rises it cools, condenses and forms towering thunderstorm clouds (cumulonimbus clouds). The rapidly rising air creates an area of intense low pressure, which the sucks in the surrounding air, creating very strong winds. This is then classified as a tropical cyclone, as it is an area of low pressure, high strong winds and heavy rainfall. However as the tropical cyclone moves over the land it loses it energy source from the high ocean temperatures and begins to fade and slow down.
Click on the following video to watch the formation of a tropical cyclone.
What are the conditions required for a tropical cyclone to form?
Several conditions are required for a tropical cyclone to form:
- High sea temperatures of at least 27 degrees Celsius
- Converging winds near the ocean surface, which forces the air to rise and form storm clouds
- Sufficient distance away from the equator to allow the Coriolis force to take effect and create the spin
Why is a tropical cyclone classed as a natural weather hazard?
A tropical cyclone is classed as a natural weather hazard as it is an extreme weather event of heavy and intense rainfall with strong high winds and strong storm surges, that puts both people lives and safety and property at risk.
What are the impacts and consequences created by tropical cyclones?
Extreme weather events like tropical cyclones can have severe impacts and consequences on the environment and communities. The intense winds created by the tropical cyclone are strong enough to destroy buildings, whole communities and communication networks. Not only are the communities and buildings at risk from the high winds, they are also at a high risk of flooding due to the intense rainfall and storm surges. One of the main consequences created by the tropical cyclones is the economic impact, with many people being left homeless and many business being destroyed.
The impacts and consequences of a tropical cyclone are different between the developed and the developing world, as the developed world have more financial, educational and economical resources to help deal with the consequences, and to help improve the prevention of these consequences.
What are the responses to a tropical cyclone?
There are both short and long term responses to tropical cyclones, with short term responses occurring before the hazard and immediately after the tropical cyclone. The short term responses often vary from place to place depending upon their knowledge of the impending hazard, and their accessibility to evacuation plans and resources. Long term responses are often focused on repairing the damage created by the tropical cyclone, and increasing their protection and prevention methods in case of future cyclones.
The responses to a tropical cyclone vary considerably between both locations and events, as each tropical cyclone is different and each location experiences different consequences, so it is easier to understand the responses by focusing on a case study.
The case study we will use is Hurricane Katrina New Orleans, 2005.
Examples of their short-term responses are:
- Declaring a state of emergency two days before the hurricane became landfall.
- Large scale evacuation attempts were made.
- However not everyone has access to transport, so they were moved to the Superdome as it was more secure.
- Organised response teams were created to provide aid.
- Housing assistance was provided to more than 700,000 people.
- Aid was provided by a number of charities and organisations, such as the Salvation Army who provided donations of more than 365 million dollars.
Examples of their long-term responses are:
- Levees are reconstructed in a stronger and more secure manner.
- New emergency flood plans have been created, to provide direction for future hazards.
- The Superdome and other damaged buildings have been rebuilt or are under reconstruction.
Is there a geographical distribution of tropical cyclones?
Due to the physical conditions required from a tropical cyclone to form, there is a distinct geographical distribution of tropical cyclones. They are distributed around the equator at 5-30 degrees. Although tropical cyclones occur in both the northern and southern hemisphere, they are more frequent and common within the northern hemisphere. Tropical cyclones are most frequently seen to hit land and create severe impacts within the USA and Asia, in the other regions they are frequently located over the seas and oceans, reducing the consequences and impacts. Below is a map which highlights the distribution of tropical cyclones.
When the winds of a tropical cyclone reach 74mph and above it becomes classified by a number of different names depending on its location. In the Atlantic and north-east Pacific ocean they are known as hurricanes, the north-west Pacific ocean refers to them as typhoons, the south-west Pacific ocean and south-east Indian ocean classifies them as severe tropical cyclones, the north Indian ocean refers to them as severe cyclonic storms, and the south-west Indian ocean classifies them as tropical cyclones.
Teaching ideas continued...
C) Working in groups of three, discuss the main overall impacts and consequences of tropical storms to try and identify the smaller impacts and divide them into three categories: Social, economical and environmental.
C) Working in groups of three, discuss the main overall impacts and consequences of tropical storms to try and identify the smaller impacts and divide them into three categories: Social, economical and environmental.