2.

Weather
Hazards

Section A:
The
Challenge
of Natural
Hazards
Geography-
Strathallan
School 1
 Key Idea Specification Content

Global atmospheric circulation helps to determine General atmospheric circulation model: pressure belts
patterns of weather and climate. and surface winds.

Tropical storms (hurricanes, cyclones, typhoons) develop Global distribution of tropical storms (hurricanes,
as a result of particular physical conditions. cyclones, typhoons).

An understanding of the relationship between tropical

storms and general atmospheric circulation.

Causes of tropical storms and the sequence of their

formation and development.

The structure and features of a tropical storm.

How climate change might affect the distribution,

frequency and intensity of tropical storms.

Tropical storms have significant effects on people and the Primary and secondary effects of tropical storms.
environment Immediate and long-term responses to tropical storms.

Use a named example of a tropical storm to show its

effects and responses.

How monitoring, prediction, protection and planning can

reduce the effects of tropical storms.

The UK is affected by a number of weather hazards. An overview of types of weather hazard experienced in
the UK.

Extreme weather events in the UK have impacts on An example of a recent extreme weather event in the UK
human activity. to illustrate:
• causes
• social, economic and environmental impacts
• How management strategies can reduce risk.

Evidence that weather is becoming more extreme in the

UK

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 Measuring
Weather: the
Elements of
Climate:
the
Weather
Atmosphere:

The cruising altitude (height) of an aeroplane is about 10km

above the ground surface. At the altitude the vast majority of
the atmosphere’s mass is below you. The atmosphere- the
air above our heads- is a highly complex swirling mass of
gases, liquids and solids. These include water droplets, water
vapour, ash, carbon dioxide and oxygen- just to mention a
few!

Global Atmospheric Circulation

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Global Atmospheric Circulation is:
What evidence do we have for Global Circulation? _____________________________________

How does wind form? Annotate the diagram below.

Explain what the weather is like at an area of:

1) Low Pressure:

Global
2) High Pressure

Atmosp
heric
Global Atmospheric Circulation is the movement of

Circulati
air across the planet occurs in a specific pattern.

on 4
The air moves across the world in cells. There are 3 cells found North and South of the Equator:
- The Hadley Cell
- The Ferrel Cell
- The Polar Cell

1. The Hadley Cell

1. The air arrives at the ________________. Here it is heated causing it to ______.

2. The air rises to form cumulonimbus clouds and _______________ and _____________________are
formed.
3. At this height, the air begins flowing polewards to ____°N and S.
4. At this point, the air begins to sink forming an area of _______pressure, resulting in dry conditions.
5. When the air reaches the ground some of the air flows back to the Equator as _________________.
6. Trade winds are important when transferring heat and moisture.

Trade Winds high 30°

Equator rise

Rainstorms Thunderstorms
The Ferrel and Polar Cells
1. The warm air continues towards the _________ along
the bottom of the Ferrel Cell.
2. Once reaching a latitude of ____°N and S, the air is forced upwards creating an area of ____pressure
bringing rainstorms.

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 3. The rising air then travels back towards the equator along the top of the Ferrel Cell or travels towards
the poles, where it cools, descends and forms an area of ____ pressure
4. Once the air descends at the poles it travels back towards the _________as wind.

high 60°

Equator

poles low

How does global

circulation affect the
world’s weather?
Global atmospheric circulation is what drives the world’s weather. The circulation cells, pressure belts and
surface winds affect the weather around the world.
1. Weather at the Equator- 0°

Describe Explanation

Areas around the equator experience:

- Hot, humid weather which is often cloudy
with high rainfall.
- Tropical rainforests can be found here.

2. Weather conditions at the Tropics- 30°

Describe Explanation

Areas around the tropics experience

- Clear skies with few clouds
- There is little rainfall

3. Weather Conditions at 55°- The UK

Describe Explanation

The UK experiences clouds, rain and mild

temperatures.

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 We also get colder temperatures with snow and
very cold winter weather.

4. Weather conditions at 90°- Polar

Describe Explanation

- Weather here is very cold with limited

precipitation

Homework questions: Use your notes to answer all questions- you must write in full sentences.
1) Why is low pressure created at the equator? What is the weather associated with this?
2) Where does the air go once it reaches the upper troposphere at 0 degrees?
3) Where is the high pressure belt located? What is the weather like here?
4) What is the air pressure at 60 degrees? Describe and explain what the weather is like here.
5) What is the air pressure like in the UK? What influences our weather?

Tropical
Storms
Tropical storms are the most violent storms on the planet and they cause tremendous destruction. They are
also called hurricanes, typhoons or cyclones, depending on their geographical location.

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Where are Tropical Storms found?

Using the map above, describe the global distribution of tropical storms [4]
1)

2)

3)

4)

Why do tropical storms not form at the

equator?

How do Tropical Storms Form?

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Scientists are not certain what causes the formation of a hurricane, but it involves the sequence of events
below.

Task: Rank the order of events which forms a tropical storm.

A strong upward movement of air draws water vapour up from the ocean surface. 1

As the Tropical Storm is carried across the ocean by prevailing winds, it continues to gather strength.

As the air condenses it releases heat which powers the storm and draws up more water from the
ocean.

The Tropical Storm now develops an eye at its centre where air descends rapidly. The outer edge of
the eye (eyewall) is where the most intense weather conditions are felt.

This evaporated air cools as it rises and condenses to form towering thunderclouds.

Several smaller thunderstorms join together to form a giant spinning storm. When wind reaches
120km/h the storm officially becomes a Tropical Storm.

On reaching land the Tropical Storm’s energy supply (evaporated water) is cut off. Friction with the
land slows it down and it begins to weaken.

What conditions need to be present for a storm to form?

1. A large tropical ocean where average sea surface temperatures exceed 26°C and the warm water
layer is at least 60 metres deep
_______________________________________________________________________________________
_______________________________________________________________________________________
_______________________________________________________________________________________
2. They form between_____________ north and south of the equator. The low pressure area has to be
far enough from the equator so that the Coriolis force creates rotation in the air mass

3. No vertical wind sheer so

4. Uniform __________________, ____________________ and ________________

Structure of a Tropical Storm

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Describe the forecast over a location as a tropical storm passes.

How does a tropical storm stop?

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 The Saffir- Simpson Scale
Tropical Storms are measured using the Saffir-Simpson scale.

Questions: Distribution and Formation of Tropical Storms

1) In which parts of the world are tropical storms called cyclones [3]
1) Why do Tropical Storms not form at the Equator? [3]
2) Describe the global distribution of Tropical Storms [4]
3) Explain the formation of a Tropical Storm. You can use a diagram in your answer. [6]
4) Explain why certain conditions are needed for the formation of Tropical Storms. [8]
5) Describe the weather conditions of one location as the Tropical Storm passes overhead
[5]
Case
Study-
Typhoon
Haiyan 11
 Location:

Date:

Wind Speed:

Wave Height:

Deaths:

Areas affected:

What happened?
In ________________ 2013 ‘Super’ Typhoon Haiyan hit. The _______________. Haiyan was classified as a
category ______ storm on the _________________________ scale. The storm had winds of ______ that
battered huge areas across the country. The strong winds caused a rise in sea level leading to a massive _____
metres high storm surge. The floods caused by the storm surge and heavy ______ led to 90% of the city of
_____________ being destroyed. The total number of deaths was about ________ with most being drowned.

Effects of Typhoon Haiyan

Primary Effects Secondary Effects

- About 6300 people killed most drowned by

the storm surge

- Over 600,000 people displaced and 40,000

homes damaged or flattened- 90% of
Tacloban city destroyed.

- Tacloban airport terminal badly damaged.

- The typhoon destroyed 30,000 fishing boats

- Strong winds damaged buildings and

powerlines and destroyed crops.

- Over 400mm of rain caused widespread

flooding.

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 Protection from Tropical Storms- Annotate the image with features of Tropical Storm
Monitoring and Predicting Tropical Storms shelters
Modern technologies allow monitoring and prediction of
tropical storm direction and strength. This allows people to
___________ or begin to put protection measures in place.

The National Hurricane Centre in Florida issues two levels of

warning:

1)

2)

Planning for Tropical Storms

What examples of planning for Tropical Storms were used in

the Phillippines and Bangladesh?

What other forms of protection (other than shelters) can be used?

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 Weather
Hazards
Question: What is the difference in and weather?
between climate

the UK

Weather Hazard:

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What different types of weather hazards do we get in the UK?

Hazard: _________________ Hazard: _________________

What is it? What is it?

When/Where has it occurred? When/Where has it occurred?

What are the effects? What are the effects?

Hazard: _________________
Hazard: _________________
What is it?
What is it?

When/Where has it occurred?

When/Where has it occurred?

What are the effects?

What are the effects?

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Extreme Weather in the UK
There have been many extreme weather events in the UK throughout history. However, scientists have
noticed that these events seem to be occurring more frequently than in the past.

What UK weather records have been broken by extreme weather events since 2000? Give 6 examples below

Why might extreme weather events be on the increase?

1)

2)

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 Highlight the following article with key points and underline anything you do not
understand.

Could our weather patterns be getting ‘stuck’?

Weather systems cross the UK mainly from west to east, driven by winds from the jet stream. The jet stream
moves north and south but can ‘stick’ in one position, resulting in a long period of the same type of weather,
such as heavy rain or drought. A large area of high pressure over Northern Europe can block the easterly
movement of weather systems and have a similar effect on UK weather.

In 2014 scientists in Germany published a report. It suggested that in recent years weather patterns have
become ‘stuck’ for long periods of time. This has resulted in prolonged periods of high temperatures
(heatwaves and droughts) and heavy rain (floods).

These periods seem to have become more frequent in recent years and this could be due to climate change. A
warming Arctic, for example, may slow down the atmospheric circulation in the northern hemisphere mid-
latitudes resulting in the weather ‘sticking’ for long periods of time. This could explain the recent heatwaves
and floods

Exam Question

June 2007 was the wettest month recorded in Yorkshire

since 1882 (over 250mm) and May, June and July were
the wettest since records began in 1760.
On 25th June, a depression became slow moving over
the UK, giving a long period of heavy rain across
Lincolnshire, Yorkshire and the Midlands, which led to
widespread flooding.
Previous heavy rain (over 80mm) had occurred on 14-
15th June, leaving soils saturated and causing some
localised flooding.
Further rain occurred on 20th, 23rd, 24th June. On 25th
June, 110mm of rain fell in 24 hours, so drains
overflowed and flooded low-lying districts of the city.

Study the information above which describes floods in Hull in June 2007. Use Figure 8 to give evidence that
supports the following statement: ‘The UK weather is becoming more extreme’. [4 marks]

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