Contending with extreme situations

How can we best respond to and cope with the impacts of extreme weather?

Key idea: Adaptation vs. Mitigation 

Extreme weather can bring some very adverse impacts onto area socially, economically and environmentally. So there are ways of dealing with it. We can either adapt to the situation or mitigate. Adaptation is usually used in  these event because these event are either caused by complex human causes such as climate change or natural such as the Milankovitch cycles which are hard to mitigate. Below I have defined each term as it is important to  understand them:

Adaptation: Any change in the structure or functioning of an organism or system that makes it better suited to the environment. For example; Boscastle is a flood prone village thus they have changed the shape of the river so it can hold of more water and cutting the impacts of flooding - not causes.

Mitigation: The process by which you make something less harmful or serious. For example; it is claimed the European heatwave in 2003 was caused by climate change. So people governments have got together like in the Copenhagen  treaty to discuss how we can cut carbon emission to mitigate climate change.

Key concept: Short-term strategies vs. long-term strategies 

Short-term strategies used to contending with difficulties with extreme weather can include increasing the number of medical staff around or evacuating people from a certain area. LEDCs tend to rely ons short-term strategies as they cannot around long-term strategies and they also rely on foreign aid for the short-term strategies.

Long-term strategies tend to be hard engineering and quite costly. The work in reducing the impacts in the long term. So for example to reduce the impact of cars being swept away by floods, Boscastle raised the level of the car park and added extra barriers to it.

How are was Hurricane Katrina predicted?

Wind speed and temperature across hurricane forming regions are measured with satellites.On these satellites we can even see the cloud formation and swirling winds. From these meteorologists can predict hurricanes. Hurricane Katrina was predicted accurately 6 days before. The official hurricane forecasting organisation is the 'National Hurricane Centre'.(Link: http://www.nhc.noaa.gov/ )

The hurricane was so violent that people were commanded to evacuate. However, 20% of the population (low income groups) didn’t have their own private transport or due to financial reasons were not able to evacuate and were left stranded in the disaster.

What did strategies did the environmental agency take in Boscastle?

They went for 4 long-term hard engineering strategies to reduce the impacts of flooding. 

1. The environmental agency made a decision to lay a large relief culvert that would carry excess rainwater. It is twice the size of the old one. 
2. The River Valency is being widened and lowered from the lower bridge to the car park, so that it has a bigger capacity and can carry more water.
3. The height of the car park is being raised using stone removed from the river bed. Also barriers are being made for the car park so that if it floods it takes much longer for the cars to be swept away.
4. There are plans to demolish the lower bridge near the harbour and replace it with a higher bridge further downstream. This will give the river more capacity and help to reduce flooding.

Risk assessment 

Risk assessment is way in which organisations such as the environmental agency can decide whether certain solutions are suitable to the particular hazards.

Boscastle flood risk assessment is done by a method called recurrence interval. It is a graph which displays the probability of floods of different levels occurring. The 2004 flash flood had a 1 in 400 years chance of coming. This does not mean the next one this big will happen after 400 years it could happy after a month and then not happen for 800years. Therefore, it isn’t particularly accurate.

Role of Technology 

As technology advances we are able to predict events faster and more accurately and we are able to find solutions which are more smart and suited to our environments.

So for example in the case of Hurricane Katrina the National Hurricane Centre were able to use new satellites to predicted accurately the hurricane would come in 6 days and help the resident of the New orleans prepare for it.

The met office use technology to forecast weather and throughout time the technology has become more efficient and accurate. For example, the snow we experienced in December 2009 and January 2010 the met office were able to give severe warnings about.

Technology is also used to reduce the impacts if disaster. River Flooding can be a great disaster and in a city like London if there was a big flood so much would be destroyed. With technology engineers were able to create the Thames Barrier which has helped reduce the risk of flooding.

GIS (geographical information systems) is a complex computer system which will show you the geography of an area including demo-graph, physical landscape and buildings in an area. They can be used for flood monitoring because they can monitor flood levels and with the weather forecast; meteorologists can put 2 and 2 together to prepare for a flood.

In extreme heat event like drought technology has been useful here as well because through genetic modification we have been able to create drought resistant crops which means that even in the worst conditions farmers will still have agricultural goods to distribute.

National Oceanic and Atmospheric Administration

NOAA is a similar organisation to the met office and national hurricane centre. They forecast weather, give warning and advice people of coping methods. They use the latest technology and produce some very accurate results. Check their about me section out: http://www.noaa.gov/

Increasing the risk of extreme weather...

How are people and places increasingly at risk from and vulnerable to extreme weather?

We are increasing our risk to these events by both human and natural causes.

Human;

1. Global warming - all over the globe scientists are saying that global warming is creating more and more disastrous events like heat waves, droughts, floods etc.
2. Demographics - Our population is increasingly on such are large scale that now it is hard to split resources evenly. This is also means that more people are living within one area of land so when there is a extreme weather event like a hurricane more people than before are being affected.
3. Land management - As we become more technologically advance and progress; more and more land become urbanised. This means that we have to exploit nature i.e. deforestation, dig land for precise resources. This leads to increased risk of flooding, more people in extreme weather prone area and more risk of destruction.

Natural;

1. Sunspots - Variations in levels of solar radiation levels can have effects on the Earth’s climate. Increased solar activity can have short-term warming effects on Earth.
2. Volcanoes - Volcanic eruptions such as Mount Tembora in 1815 can have major effects on the Earth’s climate because of the huge excretion of volcanic dust and various gases.
3. Milankovitch cycles - extreme weather is affected by changes in climate and according to one theory the Earth’s orbit varies every 100,000 years which means its distance from the sun and glaciation cycles vary. 

Increasing the risk 2004 Boscastle Flash Floods 

Lets first remind ourselves of the location of Boscastle....

View Boscastle in a larger map

Meteorological reasons why the flood risk was increased:

1. Localised rain; There was a trough passing straight through Boscastle which meant that rainfall in boscastle was 184mm and in surrounding areas only 1.5mm.
2. The trough was part of a depression which had develop over the eastern atlantic ocean. In this the air had even sucked in remains on Hurricane Alex in the USA.

Physical characteristics of the place that increased the risk.

1. The village is based at the bottom of a steep hill.
2. The upper part of the village has been urbanising recently which means deforestation increased there.
3. The overall land use of the area has been changing - it is becoming more and more built up. The consequence of this that there are more impermeable surfaces and surface runoff is increased.

So how was the flood managed?

4 long-term hard engineering defence systems were put into place to reduce the risk of such a destructive flood happening again. It cost £4.6 million.

1. The environmental agency laid a large relief culvert that would carry excess rainwater (a bit like a drain). It was made twice the size of the old one.
2. The river shape is being altered. The River Valency is being widened and lowered from the lower bridge to the car park, so that it has a bigger capacity to carry water.
3. As the so many cars swept; the car park is now being raised with stone from the river bed and barriers are being added to it so next time less cars are swept away.
4. There are plans to demolish the lower bridge near the harbour and replace it with a higher bridge downstream. This will give the river more capacity and help reduce the impacts of flooding.

For more information on the Boscastle Flash Flood in 2004 please see my post on Boscastle 2004 flood.

Impacts of extreme weather

What are the impacts of extreme weather on people, the economy and the environment?

I have linked an electronic copy of a table I created to depict the impacts.

https://docs.google.com/fileview?id=0B22KJ7SMmkOyOGFjY2VhZjQtZTQ5ZS00M2Q1LWE2MmQtOGIxZjBhNzQyMjJm&hl=en

Click the link above.

Click on photos to enlarge them...

Introduction to extreme weather

This post aims to answer the enquiry question: What are extreme weather conditions and how and why do they lead to extreme weather events?

What are extreme weather events?

They are severe and usually unanticipated weather conditions which cause chaos and disruption to our lives.

Why do they occur?

They occur for several reasons from global warming to natural changes in Earth e.g. El Nino.

Lets look at some extreme weather events...

Blizzards

A storm with widespread snowfall accompanied by strong winds. This is formed when there is a ridge of high pressure. It is when a region of high pressure interacts with an area of low pressure. It forces the warm high pressure air to rise up and cool and condense. As a result, snow falls with strong winds.

Drought

A long period of abnormally low rainfall, especially one that adversely affects growing or living conditions. This is caused by high pressure systems causing a blocking high. This means that the same hot and dry conditions in an area last for day upon end.

Fires

If temperatures get too high this can initiate forest fires and other fires throughout the country. e.g. in the European Heatwave 2003, Portugal experiences many forest fires. 

Flooding

A downpour of precipitation which causes water stores to over flow. 

Heatwave 

A heat wave is prolonged period of excessively hot weather, which may be accompanied by high humidity.

Precipitation 

It is any product of condensation that occurs in the atmosphere that falls on the Earth's surface; it can include sleet, ice, snow, rain, etc.

Summer Anticyclone

An area of high pressure in the summer which may lead to a heatwave. 

Temperate storms 

Any storm that happens in a temperate area i.e. in the middle latitudes rather than tropical or sub-tropical.It is also another name for a depression.(Depression: An area of low atmospheric pressure.)

Tornadoes 

A violently rotating column of air, falling from cumulonimbus cloud, and nearly always observable. They form like depressions in areas of low pressure. 

Tropical cyclones (hurricanes)

    
They are low pressure weather systems which have very strong sustained winds over 120 km/h are bring torrential rainfall. To find out more about how hurricanes form please look at my post on hurricanes

Winter anticyclone 

An area of high pressure in the winter that may lead to snow or ice and below freezing temperatures.

Air masses

They are large bodies of stable air that have acquired the characteristics of the areas over which they have been resting.

There are 4 types: 

Polar Continental 

Large bodies of air rest of cold areas of land. For example in the UK this air mass comes from Scandinavia, Siberia and Eastern Europe. As it travels down it warms and becomes more unstable. In the UK this brings snow, ice, cold snaps of air.

Polar Maritime 

Large bodies of air rest in cold areas of water e.g the ocean or lakes.  For example in the UK it comes from the Arctic water. As it travels down it warms up and becomes unstable. In the UK it brings precipitation, frost and fog.

Tropical Continental 

Large bodies of air rest in hot areas of land e.g. Southern Europe and America. As it travels it cools and becomes more stable. In the UK it brings hot, dry and often dusty conditions. We sometimes experiences red snow with this air mass.

Tropical Maritime 

Large bodies of air in hot areas of water e.g. Atlantic Ocean. As it travels it cools and becomes more stable. In the UK it brings warm, humid and sunny weather. Along with showers, fog and cloud cover.

Pressure Systems 

Air pressure is force pushing down on the Earth. If it is high then air is sinking and tends to move is a clockwise direction and an area with high pressure is known as an anticyclone. If air pressure is low it tends to rising and this forms clouds and an area of low pressure is know as a depression.  Air pressure can be measured with a barometer; see my post on weather instruments for further detail.

Can summer anticyclonic conditions be classed as an extreme weather event?

What are the weather conditions shown in this synoptic chart?


It is showing a summer anticyclone. We can see high pressure (pressure over 1000) and clockwise winds. Typically in this conditions the air mass is Tropical Continental - warm and dry winds from places like the Sahara. We can see no rain as in summer anticyclones we do not see much cloud formation as it is high pressure.There are light winds over England and Eastern Europe - we can see this through the knots and gap between the isobars.  However Scotland an Ireland have higher wind speeds and more cloud cover. 

There is also an occluded front passing over this part of the UK - traditionally we do not see front in anticyclonic conditions- but just goes to show the weather isn't as simple as the textbook suggests. The occluded front occluded front occurs where a warm front and a cold front meets. the means the amount of warm air that rises is larger than just a warm or cold front. This means that in that area there will be a down pour of torrential rain possibly.


What is an extreme weather event?


It is severe or unusual weather conditions e.g. hurricanes which causes severe impacts on the environment, economy and people.


So what are the risks associated with this weather system?

1. As temperatures can become extremely high we will see many health risks of dehydration etc and this worst affects the elderly and the young.
2. Water levels can become extremely low which means hydroelectric power and thermal power station may have to shut as the cooling process becomes impossible.This is dangerous because it is in a time when people will need Air conditioning in their homes.
3. Once again there is a high risk of fog, which is hard to forecast, and this may cause breathing difficulties. Especially because pollution can get caught in sinking air causing smog - which is terrible for asthmatics.
4. In extreme event 'blocking highs' can occur where the normal pattern of weather is diverted and we are stuck with the anticyclone for long periods of time.

For a real life example look at my post on the EU heatwave in 2003.

Can winter anticyclonic conditions be an extreme weather example?

What are the weather conditions shown in this map?


Firstly there is an winter anticyclone. The pressure is over 1000 (high pressure) and winds are blowing in a clockwise direction. There is also quite a large gap between isobars showing winds aren't that high which fits in the model of a winter anticyclone. There will be hardly any clouds allowing the sun to shine through although the temperatures will still be low as there is a lack of clouds which allows heat to escape back into the atmosphere. We can see this through the symbols on the chart. The winter anticyclone has built up through cold and dry condition in Scandinavia and Eastern Europe. The Polar Continental air mass is the main one associated with this weather system.


There is also a cold front passing through North East England and Scotland. Traditionally, in anticyclonic conditions we do not see fronts forming but it just goes to show that real weather is much more complex than what the textbook says. In this front the cold air advances and force the warm air to rise sharply.

When the warm air rises quickly is condenses and causes a short rapid snap of heavy rain. Hence around the front we see symbols of rain.


What is an extreme weather event?


It is severe or unusual weather conditions e.g. hurricanes which cause severe impacts on the environment, people and economy.


So what are the risks with this condition?

1. Firstly, temperatures can become extremely low bringing many health risks like hypothermia especially to children and the elderly.
2. Many who suffer with breathing difficulties will probably have many problems. This is because first off the air is cold and dry and secondly there is a high risk or fog which is known to making breathing difficulties bigger.
3. Fog is difficult to forecast in these situations do to cloud cover or the lack of it! This makes forecasting difficult and when extreme anticyclonic conditions are arising it is hard to forecast hence hard to act appropriately.
4. Some extreme situations see heavy snow of ice falling. As we have seen in the last too months this can cause severe disruption. Many lives are lost, over a million people are not able to reach work and livestock are dying as they are not able to cope with these cold conditions.

Hurricane theory, fieldwork and Katrina

1) Hurricane Theory


(i) What is a hurricane?
    
They are low pressure weather systems which have very strong sustained winds over 120km/h are bring torrential rainfall. Cyclones, typhoons and hurricanes are all names for the same weather event.


(ii) How do hurricanes form?


Firstly, for hurricane to develop certain conditions are needed e.g. sea temperatures over 27°, wind speeds need to be constant at ground level and at 12km above ground level and it needs to be in the trade wind belt between latitudes of 5° and 20°.


In low pressure conditions, the air draws in the water vapour from sea. As the air rises, it spirals up. By the time the hurricane gets to land there is air still spiralling upwards. However, the air which has already reached the top has cooled and condensed and this is what causes the torrential rainfall. 


Further, for hurricanes to occur wind speed is already relatively medium to high and the upward spirally of unstable warm air causes the wind speed to increase.


(iii) Why do hurricanes form


They form because during spring and summer there is an imbalance between atmospheric heat and the Earth's heat energy. They form because the sun heats the upper portion of the ocean and a lot of heat energy builds up as a result of it. To remove this amount of heat energy, condensation takes place in the atmosphere. 


(iv) Where are hurricanes usually found?


They occur around equatorial countries and are created in oceans in the equatorial region for example; the Gulf of Mexico, the Bay of Bengal and the Indian Ocean.


2. Hurricane fieldwork


(i) How can we measure the magnitude of a hurricane?

They are measured through a Saffir-Simpson scale where the rating of a hurricanes is based on wind speed, storm surge (rise in sea level because of low pressure and strong winds) and damage. See table above.


(ii) How can we predict hurricanes?


Wind speed and temperature across hurrricane forming regions are measured with satellites.On these satellites we can even see the cloud formation and swirling winds. From these meterologists can predict hurricanes. Hurricane Katrina was predicted accurately 6 days before. The official huricane forecasting organisation is the 'National Hurricane Centre'. (Link: http://www.nhc.noaa.gov/ )


3. Hurricane Katrina


(i) What is the location, date and any crucial facts of the hurricane?


Location: New Orleans
Date: 29th August 2005
Rating: Category 5
Wind speed: 175 mph
Rainfall: up to 16 inches in some areas


(ii) What were the causes?


Physical
(a)Hurricanes have always occurred and are a way of nature balancing heat.
(b)The city of New Orleans is below sea level; it survives by having levees and flood walls at each side of the city.


Human
(a) Well global warming is causing sea levels to rise which makes it easier for hurricanes to form and reach high intensities is one theoretical cause.
(b) Due to the construction of levees wetlands which were one form of natural defence against hurricanes are disappearing at 25 square miles per year!


Something to think about: should the New Orleans have grown to the size it did in such a perilous location.  Added to that the fact that the levees have not been maintained properly.


(iii)What were the impacts?


Social


(a) 1464 people died.
(b) 80% of the people managed to evacuate but 20% who remained were frightened and traumatised (this 20% consisted of particularly poor people)
(c)Every aspect of life was disrupted; people lost jobs, financial securities, families and health.
(d)Many residents moved to other parts of of the U.S.A - in particular Housten (Texas)
(e) There were many health concerns due to lack of clean water, food and toilet facilities.
(f) 600,000 pets were either killed or stranded in the disaster.


Economic


(a)Everyone became unemployed; people lost so much of  their financial stability that the government wasn't able to collect taxes.
(b)In 2006, it was calculated that the cost of repair and reconstruction was $10.5bn.
(c)Total economic impact was over $150bn.
(d) Oil and gas production was affected hence prices of these resources and joint goods e.g. petrol rose in price too.


Environmental


(a)There was a significant damage to forestry.
(b) The city incurred severe flooding; it was so bad that by the 31st August 80% of the city was underwater.
(c)Almost all infrastructure was destroyed.
(d)Levees and flood-walls protecting the New Orleans breached.


(iv) How was the hurricane managed: what were the responses?


(a) People were instructed to evacuate.
(b) Within a year levees were repaired.
(c) Temporary floodgates and pumps were put around four main canal entrances to prevent further flooding and damage.
(d) Weirs (low-head dams) were put in place to regulate the flow of the Mississippi River Gulf Outlet (which is a river which comes from the Gulf of Mexico).
(e)Wetlands are being restored as a natural form of protection from future hurricanes.
(f) Improvements are continually being made to preparation plans e.g. more education is given in schools, awareness weeks happen once a year etc.


The lack of a decent local and national government response to evacuating people who could not get out themselves in personal transport which made it seem more like an LEDC disaster


Coast 2050 is a $14bn , 30-year scheme to help protect the area. It includes flood controls, water diversion and coastal restoration. Through this the government will create more marsh land and set up many other defence systems.


(v) Who were the key players involved?


(a) the National Hurricane Centre
(b) Local authority
(c) Central government
(d) Local residents
(e) Emergency services
(f) Engineers

Europe Heatwave 2003

The heatwave was unanticipated, chaotic and unexpected. Heatwaves can be seen as shorter versions of droughts. The heatwave was considered an extreme weather event . It was caused by unusually high pressure conditions. What makes this case study interesting is that the question lies was this a first taster of climate change of was it part of nature’s cycle?

Location: The continent of Europe

Date: August 2003

What happened in a nutshell?

Europe experienced a prolonged summer anticyclone. The hot and dry conditions caused problems with levels of water, crop production and the health of the young and elderly.

Human causes...

1. The highest temperatures were seen in the urban heat islands; they are where the most carbon is emitted and overland runoff is experienced. These factors help conditions become more severe.
2. It is important to recognise that though humans didn't contribute much to the causes they sure made things a lot worse with global warming and much more.

Physical causes...

1.  The tropical continental air mass brought in an anticyclone. [In a summer anticyclone we experience clear settled conditions which can lead to long sunny days and warm temperatures.Weather is normally dry, but occasionally very hot temperatures can lead to thunderstorms.] Pressure became as high as 1030mb.
2. In an urban heat island the area does not cool through evopotranspiration.
3. The prolonged time period was created by a blocking high. The high pressure stuck over the UK and the normal tracks of depressions had changed. This meant that some other parts of the world experienced more depressions than usual.

Social impacts 

1. Human death toll exceeded 30,000 due to aliments such as dehydration. 
2. Nuclear plants had to shut down as cooling process was impossible because the water levels were extremely low. 
3.  Public water supplies were at dangerously low levels.
4. Hydro-electric power became near to impossible to use.
5. The London Eye was forced to close one day as it became dangerously hot within cabins.

Economic impacts  

1. Farmer's livestock and crops died and it cost them nearly £7 million.
2.  As a result food prices rose which meant the poor were eating and drinking less. 
3. Demand for electricity increased because of increased use of air conditioning systems and other cooling devices.
4.  Tourism in parts of UK increased helping the local economy.
5.  Transport/infrastructure suffered e.g. trains derailed and road surfaces melted therefore the government had to increase spending in this section.

Environmental impacts 

1. Fires broke out in forests in Europe destroying habitats and important vegetation. Furthermore, it had cost Portugal (which was affected worst by this) 1 billion euros. 
2. Total glacier volume loss in the alps was 5-10% in 2003.
3. The Danube river in Serbia was at its lowest level ever in about 100 years.

Management


Short-term responses

1. Increase the number of medical staff on site to treat illnesses caused by the hot weather. 
2.  Extra ice cream vans were  brought in to help the tourists to cool off in the hot weather.
3. Extinguish forest fires and evacuate people who live nearby to protect people. 
4. Encourage people to visit elderly friends, relatives and neighbours to check they are coping in the heatwave.
5.  Give people advice on the tv/newspaper on the best ways to cope with effects of the heat. 
6. Bring in extra emergency refrigeration units to store large numbers of dead bodies.
7. There was a temporary ban on hose pipe usages throughout Europe.
8. If temperatures reached over 30° then trains and other motor vehicles would have to comply with further speed restrictions.
9. Some people changed there working hours to make their job more bearable so for example garbage collectors worked earlier in the morning when temperatures were lower rather than in the afternoon.

Long term responses

1. Reduce carbon dioxide emissions which contribute to climate change. 
2. Install air-conditioning and alert-call systems in homes for the elderly. 
3. Build desalination plants to help increase public water supplies. 
4. Improve seasonal weather forecasts and climate predictions to help plan for future summer hot weather.

Worst affected country:

France; The French incurred the biggest temperature increase. Some places in France saw  an over 9 degrees rise whereas in the UK- maximum it was a 6 degrees rise.

For more information check out: http://www.metoffice.gov.uk/education/teens/casestudy_heatwave.html

Using weather instruments - fieldwork techniques

In this post I am going to list 13 instruments used in meteorology. In the case of flooding we will use these instruments as well as other methods and instruments such as using a GIS map or studying land-use. Images can be found below.

1. Stevenson screen: It is an instrument designed to shield meteorological instruments against precipitation and heat radiation. As well as at the same time allowing air to circulate freely around the device. 
2. Anemometer: This is a device used to measure wind speed and direction.
3. Soil Thermometer: This measures the temperature of the soil.
4. Digital thermometer: This takes more precise and accurate readings (to 0.1°) than analogue thermometers.
5. Maximum-Minumum thermometer: For a given period they will give you the range of temperatures e.g. 5-15°. 
6. Rain Gauges: After 24 hours of being outdoor the device is collected and the amount of water is measured.
7. Barometer: It measures pressure and there are three types; aneroid (needle), water and mercury. The most popular are aneroid.
8. Ventimeter: Another device used to measure wind but it more accessible as it is more cheaper. However, it does not work in low wind conditions.
9. Beaufort scale: This is qualitative data based on individual subjective descriptions. A great way to understand this is to watch this 24 sec video:  http://www.youtube.com/watch?v=4ZR0aiwtA8c .
10. Campbell- Stokes Sunshine recorder: It is used to record sunshine hours.
11. Light-meter: Meteorologists measure heat radiation from a light reader. However, the light-meter will record reflected light as well as incident light.
12. Wet and Dry hygrometer: It consists of two thermometer look-like devices and reading are taken of both of them. According to the magnitude of the difference between them we can see how humid a place is. However, it is not suitable for microclimate measurements.
13. Whirling Psychrometer: This device is whirled above the head (rather like a football rattle) for 1 minute and readings of the two thermometers are taken.