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Australia Natural Disasters
Australia - a land of droughts and flooding rains, cyclones, and bushfires. All about Australia's worst natural disasters and their effects.
348 Questions
When did harry power became a bushranger?
Harry Power became a bushranger in the early 1860s, around 1863, after he turned to a life of crime following his release from prison. He gained notoriety for his daring robberies and ability to evade capture, becoming a prominent figure in the Australian bushranging scene during that time. Power's exploits continued until his eventual capture in 1864.
What causes the ground to split in droughts?
During droughts, the lack of moisture in the soil can cause it to shrink and crack, leading to the ground splitting. The loss of groundwater and shrinking of clay-rich soils are common factors that contribute to the ground splitting during drought conditions.
Why does Australia experience bushfires?
Australia's dry climate, tendency to drought (which dries out the vegetation) and extended summer heatwaves in the south all contribute to the high incidence of bushfires. During summer, masses of hot air head east and south from the overheated centre of the continent, contributing to the conditions. The great number of eucalyptus trees also contribute to the severity and extent of bushfires as, when overheated, the eucalyptus sap can literally blow the top off the gum trees and spread the fire.
Bushfires are fires which occur in the Australian bush, usually native bushland, which quickly spread out of control. They may last a matter of hours, or up to three weeks, as in the case of the deadly 2009 "Black Saturday" bushfires.
Bushfire is also the general term for any grassfire that occurs in rural areas.
Bushfires are common in Australia's southeast up to the Queensland/New South Wales border during the summer months, and again further north around Rockhampton. They also occur regularly in the southwest of Western Australia. The intensity of bushfires is increased by dry vegetation, often after a period of heatwave, together with strong, gusting winds, and absence of precipitation. Hilly or mountainous terrain is more prone to bushfires than flat land, where bushfires can be more easily controlled.
Statistics indicate that most bushfires are caused by lightning strikes. Bushfires are, unfortunately, also commonly caused by man's activities, whether arson or unintentionally lighting the fires such as by tossing cigarettes out of car windows, or not extinguishing campfires properly. Faulty power lines are also often a cause. Sparking and arcing from these powerlines easily ignites into bushfires.
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What is the economic impact of rusting?
Rust is associated with degradation of iron-based tools and structures. As rust has a much higher volume than the originating mass of iron, its build-up can also cause failure by forcing apart adjacent parts - a phenomenon sometimes known as "rust smacking". It was the cause of the collapse of the Mianus river bridge in 1983, when the bearings rusted internally and pushed one corner of the road slab off its support. Rust was also an important factor in the Silver Bridge disaster of 1967 in West Virginia, when a steel suspension bridge collapsed in less than a minute, killing 46 drivers and passengers on the bridge at the time.
Kinzua Bridge in Pennsylvania was blown down by a tornado in 2003 largely because the central base bolts holding the structure to the ground had rusted away, leaving the bridge resting by gravity alone.
Similarly, corrosion of concrete-covered steel and iron can cause the concrete to spall, creating severe structural problems. It is one of the most common failure modes of reinforced concrete bridges.
Bushfires can destroy vegetation, wildlife habitats, homes, infrastructure, and agricultural crops. They can also have long-lasting impacts on the ecosystem by altering soil quality and water systems.
In which ocean would you NOT expect to experience a tropical cyclone?
You would not expect to experience a tropical cyclone in the South Atlantic Ocean, as tropical cyclones in this region are very rare due to unfavorable conditions such as cooler sea surface temperatures and higher wind shear.
What conditions can cause a bushfire?
There are several natural and man-made factors that can lead to bushfire conditions.
- Atmospheric conditions that cause lightning storms can result in bushfires. This is when a warm front meets a cold front. Statistics indicate that most bushfires are caused by lightning strikes.
- The intensity of bushfires is increased by dry vegetation, often after a period of heatwave, together with strong, gusting winds, and absence of precipitation. Droughts and prostrated heat are classic conditions for causing bushfires.
- A man-made condition that causes bushfires is sheer idiocy. Bushfires are, unfortunately, commonly caused by man's activities, whether arson or unintentionally lighting the fires such as by tossing cigarettes out of car windows, or not extinguishing campfires properly.
- High winds, coupled with dry air, can cause bushfires. Gusting winds cause faulty power lines to spark and arc, which easily ignites the vegetation into bushfires.
How do lightning strikes cause bushfires?
Lightning strikes are the main natural cause of bushfires in Australia (human activity is the main overall cause). Australia is a very dry continent with lower rainfall than other continents, particularly during the summer in southern areas. The country is drought-prone, with long, hot, dry summers in the southern states, and vegetation, as a result, becomes very dry, easily ignited and tinder for fires. When sudden storms roll in, as they often do with the clashing of warm and cold air fronts, not only are there lightning strikes which ignite the dry vegetation easily, but these small fires are quickly fanned into blazing bushfires by the strong, gusting winds that accompany these summer squalls.
What are some major natural disasters that have happened in Australia?
* Murrumbidgee River floods the town of Gundagai, June 1852: 89 killed * "Black Friday" bushfires, southern Victoria, January 1939: 71 killed * Hunter Valley floods, February 1955: 25 killed * Darwin hit by Cyclone Tracy, December 1974: 65 "officially" killed * "Ash Wednesday" bushfires, February 1983: 75 killed * Newcastle earthquake, December 1989: 13 killed * Cyclone Wanda and the Brisbane floods, December 1974: 16 killed * NSW bushfires, December 2001 - January 2002: 180 houses and thousands of acreas of National Park destroyed * Canberra bushfires, January 2003: major devastation of suburbs and surrounding areas * Eyre Peninsula bushfires, January 2005: 9 killed * Cyclone Larry hits Innisfail: 1 killed (heart attack) and ,ajor devastation of Queensland's banana crops
Were the Queensland floods preventable?
There have been many floods in Queensland in recent years, and whether or not they have been preventable has differed with the circumstances.
To some degree, floods are always preventable, but at the same time, it is almost impossible to foresee the effects of erratic weather patterns on any one area. There are standard plans and preparations that should always be made: keeping drainage pipes clear, having levee banks and emergency embankments ready, evacuation plans, etc. But there is no way to predict what weather patterns will actually do.
For example, in the late 1980s, the outback town of Charleville was inundated by floods which ravaged the town, and made it impossible for homeowners to be eligible for flood insurance. In January 2008, much of Queensland was under water as a result of extremely heavy rainfall further north in the Warrego River catchment and feeder rivers. The Charleville Flood Barrier Response swept into action and prepared the town for flooding, with levee banks and a temporary flood barrier. The town was saved, and as a result, some insurers lifted their bans on flood insurance for Charleville.
Meanwhile, those same conditions devastated Mackay, on the central Queensland coast. Mackay had been hit by floods before, and had action plans to reduce the impact - but in this case, they were of no avail. The rain that drenched the city was the worst in 20 years, and quite unexpected. If the Mackay city council had taken action ahead of time to counter such devastating floods, many people would have questioned why so much money was being spent on flood mitigation plans.
Brisbane's floods of 1974 were the result of another unusual situation. Whilst the depression which dumped hundreds of millimetres of rain as a result of Cyclone Wanda was unprecedented, it was made more catastrophic by the fact that it had already been a very wet year beforehand. And who could have foreseen that a huge container ship would break loose from the shipyards, and wedge itself across the Brisbane River just before the mouth, preventing the escape of the water to the sea?
Currently (2010-2011) Queensland is in the grip of devastating floods right across the state. Wivenhoe Dam, the huge dam that was built to help prevent a recurrence of the 1974 Brisbane floods, hit over 190% capacity. The dam was Brisbane's best defence, but even that was not enough. The combination of a La Ninaweather pattern, together with a widespread cyclone system that hit north Queensland on Christmas Day, meant that unusual amounts of rain fell, and continued to fall across an already waterlogged state. In this case, there is just no way to prevent the floods. No-one could have foreseen the wall of water that rushed through Toowoomba, which sits right at the top of the Great Dividing Range, and devastated the communities at the base of the range, then filled Wivenhoe Dam to over its capacity. On the other hand, the issue of controlled releases from Wivenhoe Dam prior to the catastrophic events of January 10 are the subject of a Commission of Inquiry.
There is no black and white answer to the question "Were the Queensland floods preventable?" Councils and Emergency services can do the best they can, but when one faces a once-in-50-years situation, there really is nothing anyone can do.
