home

> = = = __Australian Natural Hazards Task Force__ =
 * 1) [[image:Lightning_3.gif width="107" height="125" align="center"]]

__Description of Severe Storms:__
== Storms are very common throughout Australia, but sometimes they can cause great destruction and devastation. In order to be prepared for a severe storm, Australians must be educated about how to stay safe and most importantly, how to stay alive. This web page is a simple guide that will hopefully educate the people of Australia about the risks and dangers of severe Australian storms and also provide some information on protection against severe storms.== ** __What is classified as a severe storm?__ ** ( [] )​
 * According to the Bureau of Meteorology, a severe storm contains at least one of the following: **
 * ** Hail with a diameter greater than a $2 Coin **
 * ** Winds in excess of 90 km/h **
 * ** Flash floods **
 * ** Cyclones/Tornadoes **
 * **in addition to the more common thunder and lightning. **

__** So What Causes Thunderstorms? **__
 * Thunderstorms are caused by an influx of warm, moist air inside cloud formations, which have risen at high speeds onto clouds of air that are a lot cooler. Due to the great temperature ****differences, the surrounding air becomes lighter, resulting in the inner parts of the cloud freezing the water vapour and forming hail, rain and snow. The cloud then grows in size because of the increased water vapour and rapidly builds to create a storm. As the water vapour becomes liquid it can turn into hail, and the updraft movement creates inner turbulence. The force of the turbulence leads to an almost violent eruption, accompanied by loud thunder, spectacular electrical activity (lightning) and heavy rain. It may also be accompanied by heavy winds. When a thunderstorm creates hail or torrential rain or excessive wind gusts, it is classified as severe and warnings are given by the Bureau of Meteorology, advising of potential risk to people and to property, and updating people about what to expect as the storm develops and then dissipates. **




 * Most storms are not powerful enough to produce a severe storm (with hail, gale force or cyclonic winds or flash flooding). More commonly seen in Australian storms are elements like lightning and thunder, which is responsible for between 5 and 10 deaths each year. Usually accompanying these lightning thunderstorms are heavy rains and powerful winds. **



**Lightning and thunder occur in storms when friction is made between the clouds, the effect is a build up of energy that is transfered to the ground in the form of lightning. These flashes of atmospheric electricity are very hot and create devastating effects when they impact.**



**Tornadoes and Cyclones are formed when thunderstorm conditions are becoming violent and start developing close to low pressure areas with high wind speeds. The warm air rises into the clouds and the strong gusts of cooler air sweep downwards. These two air currents then combine and the dry, cool air collides with the warm, moist air and the warmer air is then rushed upwards at high speeds and the cooler air spirals down around it creating the tornado. Once formed, nothing will block its path, with the base of the tornado ripping up homes, shooting rubble into the air and destroying the landscape.**



Severe storms in Australia can occur at any time of the year depending on the region and the season, but weather patterns in Australia have been changing over the years and we are now experiencing more ‘unpredictable’ severe storm situations. Most severe storms occur in coastal regions, but over the past five years there have been occasional severe storms in central regions of Australia, including Canberra and the Hunter region of NSW, and even in Lightning Ridge and Bourke in the far west of the state. Most of Australia’s storms occur along the NSW and Queensland coast, but are also prevalent in the cities of Melbourne, Adelaide and Perth. There have been occasional severe storms in the Northern Territory, in Darwin and Alice Springs. Severe storms are considered quite separatefrom cyclones and typhoons, which traditionally affect the northern coastal regions of Australia (Queensland coast and islands, and Darwin) between December and March each year.
 * __LOCATION OF SEVERE STORMS IN AUSTRALIA__ **** __OVER THE PAST FIVE YEARS__ ** 

This map shows the cities and regions that have experienced severe storms in Australia over the past five years. You will note that most severe storm activity is centred on the coast, and encompasses a fairly wide band generally between the ocean and mountain ranges.



=== __Case Study of Natural Disaster - Severe Hailstorm of 1999 __ ===

LOCATION: NSW Coastline (Kiama-Gosford)

The most severe storm ever to hit Sydney occurred on the 14th of April in 1999 when a devastating hailstorm swept up the east coast of Australia. The hailstorm gained its classification as SEVERE when it passed over the west of Kiama, dropping huge hailstones the size of cricket balls and raining heavily, all the way up to the coast of Bundeena where it slowly changed direction (slightly NNE) and swept out over the ocean. From there, the Bureau of Meteorology believed that it would continue out to sea, but instead it changed direction again and started moving north.



The storm then ran parallel to the coastline for approximately 50 minutes, before it then re-crossed onto land. At this point the storm was reclassified as severe, but it was too late - the BOM had not yet set out any warnings because the chance of the storm re-crossing onto land was so unlikely. The storm ploughed through the metropolitan area of Sydney, through the CBD (central business district) as well as residential areas close to the city (like Sydney Airport, Randwick and the Eastern Suburbs), where it caused immense damage to property and was later declared the costliest natural disaster in Sydney’s history.



The storm weakened when crossing Sydney Harbour, and the BOM believed it would dissipate so did not set out warnings to the Northern Suburbs, where the storm was heading. To the BOM’s amazement and despair, the storm continued north for a further 20 minutes, regaining strength. It continued dropping large, destructive hail stones, along with strong winds and heavy rain, throughout North Sydney and the northern suburbs before reaching Gosford, where the storm slowly dissipated and moved out to sea in an easterly direction.



**__CAUSE:__**


 * The Bureau of Meteorology was shocked by the unpredictability and changes in direction and conditions as the storm evolved, as well as the severity of the hail and the duration of the storm. It was a storm that will always be remembered for its unexpectedness and for the lack of preparation and warning given to residents. The backlash against the Bureau of Meteorology for failing to warn Sydney-siders of the potential force and devastation of the storm has led to the Bureau issuing severe weather warnings often now as a precaution, even if an approaching storm is not considered severe.This very severe storm was classified as a super cell because of its erratic nature and extreme conditions. **

** The storm was really unexpected ** **because of the time of year (April is not usually storm time in Sydney) and because weather conditions at the time did not alert the Bureau to any impending danger. It was a calm day, with just some slight atmospheric instability, and a weak cold front moving north along the coast. In the west and southwest of the city, as far as the Blue Mountains, some light rain was falling, but the meteorological reports suggested that the general atmospheric conditions were not likely to result in a major thunderstorm. Looking back at historical records, this storm was only the second time in recorded history that hail larger than 2cm had fallen in Sydney during April, and actually only the fifth hailstorm ever recorded in April, during the 200 years that meteorological records had been kept.**

** The cause of the storm has been put down simply to the combination of the weak cold front along the coast with the rain in the Blue Mountains and west, and the erratic change of wind direction and intensity. ** **The storm started off the coast in the south of Sydney around Nowra, travelling in a north easterly direction and moving further off the coast for about fifteen minutes, but then began to gain speed and start veering northward, following the coast. As it moved it changed direction again, and by the time it reached Wollongong small hailstones were falling. It was at this point that the Bureau reclassified the storm as severe. The storm continued to change direction, so the Bureau did not see the need to issue hail warnings for other parts of Sydney, but soon Sydney Airport, Sydney’s CBD and and the Eastern Suburbs were hit with massive hailstones the size of cricket balls. Again, the Bureau thought that the storm would head out to sea, and hadn’t predicted yet another change in direction as the storm headed towards the north, gaining in strength and intensity and developing the characteristics of a severe thunderstorm. Devastation across Sydney extended all along the coast as far south as Kiama, and north to the Central Coast.**

**__EFFECTS__**:

This storm had far reaching effects, ** environmentally ** (damage to the natural environment and animal habitats as well as to property), ** economically ** (huge financial costs to individuals as well as to insurance companies and the NSW government ), ** socially ** (unhoused communities) and ** politically ** (accountability and blame placed on the Bureau of Meteorology).As the storm ploughed along the coastline, it caused over $2.3 billion Australian dollars in damage. The hailstorm of 1999 was t ** he costliest natural disaster in Australia ** with insurance costs reaching over $1.7 Billion Australian dollars. The storm significantly damaged over 24,000 homes due to the enormous holes that the hailstones created. Roughly 70,000 vehicles were damaged, mainly smashed windscreens and roof punctures. Sydney Airport suffered damage to 23 planes and helicopters because of a lack of space in the hangars. This storm established a ** lack of trust in the reliability of the Bureau of Meteorology **. The public reaction from not predicting or warning of this damaging storm ensured that the BOM would start providing warnings for any storm that is even a mild threat, and also demanded that they provide more information on the possible or potential effects of any future storms. This storm caused one fatality, when a man's fishing boat was struck by lightning only 100 metres out to sea. It was the most devastating storm in the Sydney region and has dramatically ** increased public awareness ** of the potential damage of severe storms, both to property and to people. It will long be remembered for its ferocity, unpredictability, and destruction.

The 1999 hailstorm caused great damage to coastal communities and many Australians were **reliant upon** **Government aid** to help repair property and provide emergency housing. Within hours of the devastation, Premier Bob Carr declared the worst affected areas as ‘disaster zones’ and sent emergency assistance. State Emergency Services (SES) were aided by the NSW Rural Fire Service to provide building recovery and maintenance to damaged houses and structures. The entire job used over $10 million dollars worth of tarpaulin covers to temporarily cover the massive amount of structure damage caused by the severe hail. As the tarpaulins became ineffective and started to blow away, people became desperate for permanent repairs, and many tradespeople (who were in short supply) started charging unreasonable rates for work. To manage these **social and economic issues**, the government set up a campaign to inform Australian people about choosing reliable and registered repairers, and how to avoid being ripped off.





**__MANAGEMENT STRATEGIES FOR THE 1999 HAILSTORM__**:

**This severe storm was the impetus for change and for increasing the education of people about ways of minimising risk and protecting both themselves and their property in the event of severe storms. All states in Australia now have excellent State Emergency Services, all with the same emergency number throughout Australia (132 500) which all Australians can ring for immediate, free assistance and emergency repairs in the event of a severe storm. The SES websites in each state provide excellent information and resources for people to make them aware of potential storm risks, and ways that they can both minimise their risk of injury or damage but also find resources and support. The SES is run by volunteers and supported by corporate sponsors as well as the Bureau of Meteorology.**

 **Protecting yourself against severe storms is important for your safety and to help minimise damage and destruction to property. Preparing yourself and your property against storm damage is similar to the precautions taken to minimise bushfires – simple maintenance such as pruning large overhanging branches from trees, ensuring gutters are clear of debris and maintaining clear areas around the perimeter of the house are all important, ongoing maintenance considerations. Checking your house for leaks, exposed pipes and other irregularities can prevent dangerous situations occurring during a severe storm. It is also a good idea to have an emergency kit prepared at all times, complete with torches, batteries, rubber gloves, first aid kit and a radio, and to store valuables in an accessible place for quick collection in the event of an evacuation. The SES website has full details on what to include in an emergency kit, and brochures in many languages on storm safety. **
 * __Preparing and protecting your property against storm damage__ **
 * __What to do in the event of a severe storm__ **

· **you do not leave the house! Bring children and pets inside. Stay away from windows. ** · **you park your car under secure cover if possible, and away from trees. ** · **you keep a radio (battery powered and tuned to weather updates) where it can be heard, ** <span style="font-family: Arial,Helvetica,sans-serif; font-size: 10.8pt;">· **<span style="font-family: Arial,Helvetica,sans-serif; font-size: 120%;">store spare water supplies (in portable containers) in case the supply is cut, ** <span style="font-family: Arial,Helvetica,sans-serif; font-size: 10.8pt;">· **<span style="font-family: Arial,Helvetica,sans-serif; font-size: 120%;">you try to stay in a basement or some low place where you are below the ground (or very close to it) and keep your emergency supplies with you (torches, batteries, radio, water) ** <span style="font-family: Arial,Helvetica,sans-serif; font-size: 10.8pt;">· **<span style="font-family: Arial,Helvetica,sans-serif; font-size: 120%;">do not walk, ride or drive through flood water. Stay away from power lines and trees. ** **Depending on the type of weather experienced during a severe storm, there are different techniques to stay safe.**
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 120%;">In the event of a severe storm, it is advised that: **

<span style="font-family: Arial,Helvetica,sans-serif; font-size: 130%;"> __**What to do after a severe storm**__ **When a severe storm has passed, it is important to assess damage, if it is safe to do so. Be alert to power lines, falling debris and damaged trees or property which may fall. Stay away from drains, creeks and other waterways. If your property has sustained damage that you cannot safely access or repair, contact the SES in your state (132 500) for assistance. Do not climb onto rooves to check damage unless you are well equipped with safety gear. The SES volunteers are also available to help clear storm debris, like fallen trees that are blocking roads, and to provide access to houses and businesses. Even if your property is not damaged, it is likely that you may suffer loss of power or telephone, or that exit roads are blocked. The SES are there to help you and to provide information and support, to help keep you safe and provide temporary assistance. For life threatening emergencies, ring 000. Keep listening to your local radio station for information about storm damage, and advice. If you do not require assistance, check on neighbours to see if they need help. Do not go out sightseeing. If you are a tenant, contact the Office of Fair Trading for information on reporting storm damage and gaining assistance if your property is uninhabitable. Their website has a brochure specifically for tenants.** ** __How can the occurrences of severe storms be reduced?__ ** **Much research has been done in the past fifty years to try to find ways of scientifically managing weather, to help minimise the occurrences of events such as severe storms or cyclones, or to increase the possibility of rain in drought devastated areas. Throughout the centuries, rituals and magic have been carried out by many cultures which have become the basis of many myths and legends, but scientific management began in the 1950’s with a lightning rod, and later with cloud busting experiments. Cloud seeding has been used in many countries to increase rainfall with some success, but attempts to reduce storm development have been less widely accepted. The US, in a project called Stormfury, attempted to weaken tropical cyclones by flying aircraft into storms and seeding them with silver iodide. Other efforts have included dropping large amounts of environmentally friendly oils onto the surface of oceans to prevent droplet formation, and the use of a commercially available polymer called Dyn-O-Gel which is claimed to be able to absorb 1500 times its own weight in water. The theory is that if you drop this powdered polymer into clouds you can remove their moisture, helping to dissipate the storm, and that when the gel then reaches the ocean it dissolves. Even though this product is available, it is not proven as reliably effective. ‘Hail cannons’ have been used for more than a hundred years, mainly by farmers, to supposedly ward off hail, but again their effectiveness is far from proven.**
 * ** In the event of a __Hailstorm__, stay indoors and under a well supported home. If the roof of your home becomes damaged, seek shelter beneath a strong table or desk and wait for the storm to pass. Keep away from glass. **
 * ** In the event of __Gale Force Winds__ (exceeding 90km/h) you should stay in doors under a well supported table/desk, secure and reinforce all windows and doors and wait for the storm to pass. **
 * ** In the event of __Flash Flooding__, you should gather warm clothes, a weather radio, water supplies and a fully charged mobile phone and climb onto a roof or high ground. From there you should immediately call 000 for emergency services assistance. **
 * ** In the event of a __Tornado__ __,__ find shelter in a basement or low floor and seek shelter beneath a table surrounded by unused mattresses, blankets etc. that could protect you from debris and rubble. If in doubt, seek shelter in a bathtub on the lower floors of a house (bathtubs are usually secured to the floor) and cover yourself with protective material such as towels, blankets, dounas or mattresses that can help prevent injury from falling debris. **



**It is interesting to note that for the 2008 Beijing Olympics, China made available 30 planes, 4,000 rocket launchers, and 7,000 anti-aircraft guns to attempt to stop rain falling. Each of these machines would theoretically shoot various chemicals into any threatening clouds to try to shrink rain drops before they could reach the stadium** __**!**__
 * Research into weather control and specifically storm management techniques continues, and many climatologists and scientists continue to experiment with techniques for the prevention of evaporation, or the microwave heating of storm cells and hurricanes. However the potential for serious damage to ecosystems, as well as potential accidents and health risks to people, has meant strict controls being enforced, so it could be many years before science can be used to prevent severe storms from occurring. The use of weather control as a potential weapon against enemies has led to the banning of weather control measures for warfare by the United Nations!**


 * The following data-base contains information on a variety of natural hazards and their affects/costs on the Australian community. **

media type="custom" key="6487789"

Bibliography:
//Car Damage in Hailstorm//. //Paintless Dent Repairs and Removal//. Web. 2 July 2010. < www.paintlessdentrepairs.com.au/links.html>. Speer, Milton. //Cricket Ball Comparison with Hailstorm//. //Severe Storms//. Web. 1 Jan. <http://www.bom.gov.au/climate/environ/images/hailstones.jpg>. "1999 Sydney Hailstorm ." //Wikipedia - the Free Encyclopedia//. Web. 1 July 2010. <http://en.wikipedia.org/wiki/1999_Sydney_hailstorm>. "Facts, Warnings Protection.." //Severe Thunderstroms.//. Web. 1 Jan. <http://www.ema.gov.au/www/emaweb/rwpattach.nsf/VAP/(084A3429FD57AC0744737F8EA134BACB)~Severe+Thunderstorms+-+facts,+warnings,+protection.pdf/$file/Severe+Thunderstorms+-+facts,+warnings,+protection.pdf>. "Severe Storms in Australia." //Wikipedia//. Web. 1 Jan. <http://en.wikipedia.org/wiki/Severe_storms_in_Australia>. "Severe Storms." //Queensland Government - State Disaster Management Group//. Web. 1 Jan. <http://www.disaster.qld.gov.au/disasters/severestorms.asp>. "Severe Thunder Storms." //Australian Government -Beaureau of Meteorology//. Web. 1 Jan. <http://www.bom.gov.au/info/thunder/>. "The Sydney Hailstorm - 14th April 1999." //Australian Government - Beaureau of Meteorology//. Web. 1 July 2010. <http://www.bom.gov.au/nsw/sevwx/14april1999.shtml>. "Thunderstorms in NSW & ACT." //Australian Government - Beaureau of Meteorology//. Web. 1 Jan. <http://www.bom.gov.au/nsw/sevwx/>.