Cyclones Flashcards
Why are names attached to weather events?
It has been found to help people track it’s progress and it allows people to plan and prepare
What is a tropical cyclone?
This is a general term used to describe a rotating system of clouds and storms that form and develop over tropical and sub-tropical waters
When is a tropical cyclone a hurricane or typhoon?
When it reaches wind speeds above 118km/h
What terms under tropical cyclone are used to describe each weather event for its location on the earth?
- Hurricanes are used in the North Atlantic and Pacific coast of the USA
- cyclones are used in the Indian and South Pacific Ocean
- typhoons are used in the western North Pacific
For strong winds, what does it involve?
It can destroy buildings, lift roofs, vehicles and trees and it can destroy power lines
For storm surges, what do they involve?
High tides causing flooding which is due to low pressure as weight of air isn’t holding down the sea as much
What are the hazards that come with cyclones?
- strong winds
- intense rainfall
- storm surges
- landslides
For intense rainfall, what does it involve? Give an example
Where an Average of 1000mm of rain can fall in a single storm e.g. in 1967 typhoon Cana is China brought 2700 mm of rain (higher than annual rainfall in London)
For landslides, what does it involve? Give an example
Where rock and debris move down a slope due to saturated ground which slumps when wet e.g. in 2014, 53 people died in landslides caused by tropical storm jangmi in the Philippines
What are source regions?
The area where the cyclone forms
How big are cyclones on average
650km across
What conditions are needed for a tropical cyclone to form?
- a large still warm ocean where surface temp is over 26.5° for a long period of time
- strong winds in the troposphere that are 10-12km above the earths surface as they rapidly draw warms air up from the earth’s surface
- the Coriolis force = a strong force caused by the earth’s rotation Which is why cyclones only form between latitudes of 5°-30° away from the equator and not on it
What are the steps to a cyclone forming
- Warm air currents rise from ocean causing more air to rush in to replace it which rises as it’s drawn by the draught above
- There is alot of water vapour from up draughts of air which which condenses to produce cumulonimbus clouds
- Coriolis force causes rising currents of air to spiral around the centre of the cyclone. Air then rises and cools then some descends to form the calm eye of the storm
- The cyclone tracks away from the source and is fed new heat and moisture from the ocean causing it to grow
- Once it hits land it looses the ocean and no longer has an energy source so air pressure rises as temp falls, winds drop, rainfall decreases and it dies down to a simple storm
What are primary effects?
Events that happen immediately as a result if a hazard
What are secondary effects?
Events that happen after the hours, days and weeks after the hazard
Where was the location of hurricane Katrina?
Include the state, what it borders and use compass directions
It happened in New Orleans in Louisiana. It borders Texas, Arkansas and Mississippi in south of America
When did hurricane Katrina start and end?
From 24th August 2005 to the 30th August 2005
What category storm was hurricane Katrina
Category 4-5
What was the pressure of hurricane Katrina
902 mb of pressure which is very low making it a powerful storm
What was the wind speed of hurricane Katrina
145mph
How quickly did hurricane Katrina escalate?
By 27th of August it already became a category 3 storm
What were the social impacts of hurricane Katrina?
- 1836 people died of drowning
- 1million people got misplaced
- 100,000 temporary homes were needed
Give some economic impacts of hurricane katrina
- $100 billion worth of reparations making it the most costly us hurricane since 1930
- the dairy industry lost $12 million
- timber industry lost $5 billion
Give some environmental impacts of hurricane Katrina
- Oil rigs were destroyed polluting waters
- 90,000 sq miles of land was affected
- 9 million chickens lost their lives
Give 6 responses to hurricane Katrina
- housing was reconstructed
- FEMA helped 108,000 people with unemployment benefit
- Red Cross provided 902 shelters over 24 states
- EU sent 500,000 food rations
- China offered $5 million
- George Bush signed a $10.4 million aid package
Where was cyclone Aila? When was it?
Bangladesh on 23rd May 2009
What factors could have caused cyclone aila to have higher consequences
- bangladesh cyclone trackers had to plot data by hand and relied on Japan’s data
- 80% of Bangladesh is less than 10m above sea level
What was the width of cyclone aila?
500-1000km across
What wind speeds did cyclone aila reach?
74mph
Give 4 social impacts of cyclone aila
- 500,000 had to be evacuated to higher land
- 200 died
- 200,000 were left homeless
- disease spread quickly due to lack of sanitation causing an outbreak of diarrhoea
Give 2 economic impacts of cyclone aila
- in total cost $550 million
- 59,000 animals were killled
Give 3 environmental impacts of cyclone aila
- the sundarbahs mud embankments burst drowning at least 30 tigers
- fresh water became contaminated by sewage
- 318,000 hectares of crop land was affected
Give the responses to cyclone aila
- 3500 cyclone shelters took in 5000 people
- houses became built on stilts
- they payed japan $512 per year for use of their satellites technology to be better prepared if a cyclone hits again
What is vulnerability?
A measure if the extent to which a community or area is likely to be disrupted by the impact of a hazard
What is risk?
The probability of a hazard causing a harmful consequence like death, injury or loss of property
Give 7 factors that affect vulnerability of a country to natural disasters
- preparation
- education
- population density
- building design
- time of day
- economy
- type of sediment
For time of day, how does it affect vulnerability?
I’m the day time people are more aware and are quicker to react and so reduces vulnerability
How does population density affect vulnerability?
- In rural areas vulnerability is reduced as less people liver there so less potential lives to be lost
- this is the opposite for urban areas
For education, how does it affect vulnerability?
- People can learn to avoid and reduce hazard impacts
- I’m literate populations, written messages can be used to spread news about oncoming hazards
For sediment type, how does it affect vulnerability?
As houses built on flat secure bedrock are going to be more secure than those built on steep hills and unstable rocks
For building type, how does it affect vulnerability?
- As newer stronger buildings that can withstand certain hazards reduce vulnerability
- poor countries are going to be less able to build stable strong housing and instead will usually be weak and cheap buildings
For economy, how does it affect vulnerability?
- the poor are less likely to afford resources needed for a response and are less likely to have insurance policies
- rich tend to loose more from disasters as they are more valuables at stake
- poor are less likely to have access to medical care so it’s easier for them to be injured or killed
For preparation, how does it affect vulnerability?
- Countries with good alarms and warning systems are less vulnerable
- some hazards like floods are easier to predict
What are levees?
Artificial embankments built up in either side of a river to stop flooding
What % of cyclones does Bangladesh get each year but what % of deaths by cyclones does Bangladesh deal with?
Gets 5% of cyclones but 85% of those killed by cyclones happen in Bangladesh
Why do more people die in cyclones in Bangladesh?
People are forced to leave on cheaper flood prone land in poorly built housing
What % of people in Bangladesh live below the poverty line?
31% of the population
What methods are used in preparation for cyclones and their hazards?
Weather forecasting, satellite technology, warning systems, evacuation strategies, storm surge defences
For weather forecasting in Bangladesh, what does it involve, what’s its success and what are the future challenges?
- sends weather forecasts and warnings to tv and radio
- successful as there are 103 phones per 100 ppl so many use phones and digital systems are developing
- future challenges are that in rural areas less have access to digital devices so may not see the warning
For satellite technology, in Bangladesh, what does it involve, what’s its success and what are the future challenges?
- the three radar stations transmit live updates from japan, us and China satellites
- in 2012 bangladesh announced a spend on $150 million for a new satellite
- it’s going to be costly for the country
For warning systems in Bangladesh, what does it involve, what’s its success and what are the future challenges?
- They were developed after cyclone Bnola in 1977 which killed 200,000
- allows for quick evacuation of coastal communities and runs awareness campaigns using village posters, meetings and leaflets
- time consuming and costly to set up
For evacuation strategies in Bangladesh, what’s its success and what are the future challenges?
- the are 3500 shelters built ready to house those affected by the disaster as death rates are double where there are no shelters And they are sturdy so can safely protect refugees
- due to a growing population there aren’t enough shelters and its costly to set up and maintain
For storm surge defences in Bangladesh, what does it involve, what’s its success and what are the future challenges?
- involves use of embankments to prevent overflowing
- they can be used to build main roads on and 22km of mostly low lying rivers can be reduced of their risk
- it doesn’t protect the whole country and can fail
What are the advantages and disadvantages in the USA for weather forecasting?
+most have digital access with 79% of the pop. with a social media account
-the system is aged and people do not always follow media advice
What are the advantages and disadvantages in the USA for satellites?
+can view the whole earth at once and record the images as quick as one at every minute
-the system is aged as in 2012, a satellite failed and the back up was on a too old software. Also satellites can only give broad predictions
What are the advantages and disadvantages in the USA for warning systems and evacuation strategies?
+warning systems can help plan evacuations and classifies towns and cities into risk zones
-not always accurate and there’s pressure on emergency services from people who don’t need evacuating
What are the advantages and disadvantages in the USA for storm surge defences?
+using them saves money on having to later fix damage properties and pay back insurance
-can be expensive and some levees are poorly maintained like in New Orleans where 80% of it was left flooded for weeks after Katrina
