Weather Hazards

Question 1

Define the atmosphere

Answer 1

the complex mass of gases, liquids and solids surrounding the earth

Question 2

Define weather

Answer 2

day to day conditions of temperature, cloud, precipitation, fog/visibility, wind + sunshine

Question 3

What causes wind?

Answer 3

Air moves from an area of high pressure to low pressure. The low pressure means that air is rising, there is less air

Question 4

Order of Cells from Equator up in the global atmospheric circulation

Answer 4

Hadley Cell, Ferrel Cell, Polar cell.

between Hadley and Ferrel = High pressure descending air

between ferrel and polar = low pressure rising air

Question 5

Describe the global atmospheric circulation

Answer 5

Sinking air creates high pressure, and rising air creates low pressure.

Surface winds move from high to low pressure, transferring heat and moisture from one to another.

These winds curve due to the earth’s rotation and change seasonally as the tilt and rotation of the earth causes relative changes in the position of the overhead sun.

Question 6

How does global circulation affect the world’s weather?

Answer 6

Cloudy and wet in the UK – we are 60o north and this is close to where cold polar air from the north meets the warm subtropical air from the south. So since the boundary is unstable, the rising air cools and condenses forming clouds and rain.

Hot and dry in the desert – there they are 30o north or south of the equator, where the sinking air means that there is high pressure, little rain, hot daytime temperatures and very cold nights. Since no air is rising there are no clouds forming and therefore little rain.

Hot and sweaty at the equator – there the air is rising and there is another pressure belt called the equatorial low. It’s much hotter here since the sun is directly overhead, so it is often cloudy with high rainfall. This is where tropical rainforests are often found.

Question 7

Define Tropical Storms

Answer 7

a huge storm that developed in the tropics, they can be called hurricanes (US and Caribbean), cyclones (south-east Asia, Australia) and typhoons (japan and Philippines).

Question 8

How do Tropical Storms form?

Answer 8

1. Rising air draws evaporated water vapour up from the warm ocean surface which cools and condenses to form towering thunderstorm clouds.
2. The condensing releases heat which powers the storm and only draws up more water vapour.
3. Multiple thunderstorms join to form a giant rotating storm.
4. The Earth’s rotation spin the cloud an over 120 km/h creating a vast cloud spiral with a central, calm eye of rapidly descending air.
5. Prevailing winds drift the storm over the ocean surfaces like a spinning top, gathering energy and strength.
6. On reaching land the energy supply of evaporated water is cut off and the storm will weaken.

Question 9

Conditions for Tropical Storms

Answer 9

• mainly formed in Summer and Autumn
• Warm oceans supply the energy
• Need to be at least 26.5degreesCelsius
• Oceans take months towarm up
• Around 5-15o north or south of the equator as there the Coriolis effect (the effect of the earth’s rotation) is stronger.
• Intense heat and humidity in the tropics makes the air unstable

Question 10

Structure and feature of Tropical Storms

Answer 10

• 500-2000km long
• height = about 12km
• Eye = clearly visible, small area where relatively cold air sinks towards the ground and warms up
  = no clouds and conditions are calm.
• Eye wall = bank of cloud; strong in excess of 120km/h; heavy torrential rain; thunder and lightning
• Beyond the eye wall there are further banks of clouds with thunderstorms and occasional tornadoes
  = strong gusty winds
  = heavy rain

Question 11

Description of the Hadley Cell

Answer 11

Since it is at the equator, the sun is directly overhead, there are vast quantities of warm, moist air. This rises to about 30degrees north or south where it is cooled down again and goes back towards the equator where it is heated up again with the concentrated sun rays.

Question 12

Conditions near the equator

Answer 12

• very humid
• hot
• wet
• high rainfall
• Tropical Rainforest

Question 13

General direction of Tropical storms

Answer 13

• overall most go from east to west
• never cross the quator
• Northern Hemisphere go up north
• Southern Hemisphere go down south

Question 14

How do the tropical storms move thousands of miles

Answer 14

• the prevailing wind pushes the storm along as wells as ocean currents
• the Earth’s rotation from east to west.

Question 15

Under what conditions do tropical storms lose or gain intensity?

Answer 15

Lose intensity:

• cooler ocean
• moving on land

Gain intensity

• warmer ocean
• not over land
• Time = takes days to build

Question 16

How will climate change affect tropical storms?

Answer 16

 Distribution
The sea surface temps have increased by 0.25 – 0.5o in the tropics so it is easier for them to form and affect the distribution. Therefore, areas which are now outside the hazard zone may become affected. The storms can also become more powerful.

 Frequency
Six of the ten most active years in the north Atlantic since the 1950 have happened since the mid-1990s.

 Intensity
In the last 20 years, hurricane intensity has increased, this is linked with sea surface temperatures.

Question 17

Locational detail of the Philippines

Answer 17

• South East Asia
• Archipelago
• Pacific Ocean to the East
  South China sea to the west
• Population: 99.9 million

Question 18

Overview of Typhoon Haiyan

Answer 18

It was one of the strongest category 5 storms ever recorded. There was very low air pressure which caused a 5m storm surge which was swept on shore by winds of up to 275km/h. coastal devastation included 90% of Tacloban destroyed by the storm surge.

Question 19

Primary Effects of the Typhoon Haiyan

Answer 19

 About 6300 killed, most in storm surge.
 Over 600 000 displaces and 40 000 homes damaged or flattened.
 Over 400mm of rain caused widespread flooding.
 30 000 fishing boats destroyed.
 Airport terminal badly damaged.
 Wind damage to buildings, power lines and crops.

Question 20

Secondary Effects of Typhoon Haiyan

Answer 20

 14 million affected including 6 million lost jobs.
 Landslides and blocked roads due to flooding.
 Power supplies cut off for a month in certain areas.
 Shortages of power, water, food and shelter, leading to outbreaks of disease.
 Looting and violence in Tacloban.

Question 21

Immediate Responses of Typhoon Haiyan

Answer 21

 Rapid overseas aid.
 US aircraft carrier ‘George Washington’ assisted with the search and rescue and delivery of aid.
 Over 1200 evacuation centres set up.
 Field hospitals helped injured.

Question 22

Long Term Responses of Typhoon Haiyan

Answer 22

 UN and international financial aid, supplies and medical support.
 Rebuilding of infrastructure.
 Rice farming and fishing quickly re-established.
 Homes rebuilt in safer areas.
 More cyclone shelters built.

Question 23

Tropical Storms : Monitoring and Prediction

Answer 23

Tropical storms can’t be prevented, but they can be monitored and their tracks can be predicted so warnings can be given out and people can prepare and know what to expect.
- computer models

e.g. National Hurricane center in Miami warns people.

Question 24

Tropical Storms : Protection

Answer 24

• Cyclone shelters = very expensive but highly effective
• Storm drains = preventing flooding, cheaper option
• Sea walls to protect key properties from storm surge
• Houses on stilts = if made with strong material (expensive) but can be very effective.

Question 25

Tropical Storms: Planning

Answer 25

It is unrealistic to stop the tens of millions of people living and working in coastal areas that are at risk, so instead it can be made safer. This means to educate the communities so that they understand the dangers and how to respond to them.

Question 26

UK Weather Hazards: Thunderstorms

Answer 26

they follow hot weather bringing lightning and torrential rain linked with ‘flash’ flooding.

Question 27

UK Weather Hazards: Prolonged Rainfall

Answer 27

this over a long time leads to river floods, such as the wet winter of 2013/14. This is common in the winter when snow melt adds to the issue.

Question 28

UK Weather Hazards: Drought and extreme heat

Answer 28

this causes rivers to dry up and reservoirs to run dangerously low. The record-breaking 2003 heatwave killed 20,000 all over Europe – mostly children or the elderly.

Question 29

UK Weather Hazards: Heavy snow and extreme cold

Answer 29

they are less common nowadays but can still cause hardships to those in the north. Dec 2010 was the coldest in a century.

• usually coming in from the east

Question 30

UK Weather Hazards: Strong winds

Answer 30

such as Feb 2014, cause disruption to power supplies, damage from fallen trees and coastal battering from large waves.

Question 31

Somerset levels: Overview

Answer 31

they were caused by a sequence of south-westerly depressions which brought record rainfall in Jan and Feb. The high tides and storm surges swept water up the rivers from the Bristol Channel preventing normal flow and rivers, clogged with sediment, had not been dredged for 20 years.

• Somerset located in SW of UK

Question 32

Social Impact of the Somerset Levels

Answer 32

• over 600 houses flooded
• 16 farms evacuated
• some residents evacuated to temporary accommodation for several months
• Many people had power supplies cut off
• Villages such as Moorland and Mulchelny cut off. This affected people’s daily lives e.g. attending school, shopping etc

Question 33

Economic Impacts of the Somerset Levels

Answer 33

• Somerset County Council estimated the cost of flood damage to be more than £10 million
• over 14, 000 ha of agricultural land under water for 3-4 weeks
• over 1000 livestock evacuated
• Local roads cut off by floods
• Bristol to Tauton railway line closed at Bridge water

Question 34

Environmental Impact of the Somerset Levels

Answer 34

• Floodwaters were heavily contaminated with sewage and other pollutants including oil and chemicals
• A huge amount of debris had to be cleared
• Stagnant water had collected for months had to be reoxygenated before being pumped back to rivers.

Question 35

Immediate Response of Somerset Levels

Answer 35

 Huge media interest was generated.
 Boats were used as transport for cut-off villages.
 Community groups and volunteers gave individual support.

Question 36

Long-Term Responses of Somerset Levels

Answer 36

 £20 million flood action plan launched by Somerset county council and Environmental Agency to reduce future risk.
 8km of rivers Tone and Parrett dredged.
 Road levels raised in lowest dips.
 Vulnerable communities will have flood defences.
 River banks raised and strengthened, and more pumping stations built.

Question 37

Examples of Extreme weather in the UK

Answer 37

2003 – heatwave – highest ever temp of 38.5oC recorded in Kent. Over 2000 died, railways buckled and roads melted.

2007 – floods – several deaths and many left homeless in the summer floods.

2009 – snow – heavy snow in the south including 20cm in London.

2015/16 – floods – December 2015 wettest and warmest ever recorded.

Question 38

Causes of Extreme weather

Answer 38

These recent cases of extreme weather could be because of climate change and global warming as they lead to more energy in the atmosphere, which could lead to more intense storms, and it probably affects the atmospheric circulation, bringing floods to normally dry areas and heatwaves to normally cooler areas.