Send the link below via email or IMCopy
Present to your audienceStart remote presentation
- Invited audience members will follow you as you navigate and present
- People invited to a presentation do not need a Prezi account
- This link expires 10 minutes after you close the presentation
- A maximum of 30 users can follow your presentation
- Learn more about this feature in our knowledge base article
Do you really want to delete this prezi?
Neither you, nor the coeditors you shared it with will be able to recover it again.
Make your likes visible on Facebook?
Connect your Facebook account to Prezi and let your likes appear on your timeline.
You can change this under Settings & Account at any time.
Transcript of Untitled Prezi
Inside the firestorm...
What are Bushfires?
An uncontrolled fire in the trees and bushes of scrub land.
What are the different types of bushfires?
Surface fire- a forest fire that burns only the surface litter and undergrowth.
Spot fire- a fire started by flying sparks or embers at a distance from the main fire.
Grass fire- an uncontrolled fire in a grassy area.
The top five worst bushfires.
Thanks for watching
Facts about bushfires
How are bushfires caused?
Where do bushfires occur?
How are bushfires measured?
The speed of the bushfire is measured like the speed of a car by Km/h.
The area is measured in acres, deaths, property damage and the money spent on preparing for fires and repairing property after fires strike.
Fire danger rating signs
There are 7 different ways for how bushfires are caused...
Generally speaking, the greater the fuel load, the hotter and more intense the fire. Fuel which is close together but with consistent spacing will burn faster than heavily packed and thick or scattered fuel sources. Smaller pieces of fuel such as twigs, litter and branches burn quickly, particularly when they are dry and loosely arranged. Some types of grasses burn very rapidly, while larger fuels, such as tree trunks, do not burn as easily. The natural oil within Eucalypt trees promotes the ignition of fuel.
Dry fuel will burn quickly, but damp or wet fuel may not burn at all. As a consequence, the time since rainfall and the amount of rain received is an important consideration in assessing bushfire danger. Often a measure of the drought factor, or moisture shortage, will be used as an indicator of extreme bushfire weather conditions.
Wind acts to drive a fire by blowing the flames into fresh fuel, bringing it to ignition point and providing a continuous supply of oxygen. Wind also promotes the rapid spread of fire by spotting, which is the ignition of new fires by burning ashes lofted into the air by wind. Spotting can occur up to 30km downwind from the fire front. There is a beginning wind speed of around 12 to 15km/h which makes a significant difference in the behaviour of bushfires in the open. When wind speeds are below this start, fires with heavy fuel loads burn slowly. However, even a slight increase in wind speed above this threshold results in a significant increase in fire behaviour and advancement. The width of a fire front also has an influence on the rate of spread and a wind shift can immediately widen the forward edge of a fire.
The higher the temperature the more likely it is that a fire will start or continue to burn. This is because the fuel is closer to its ignition point at high temperatures and pre-heated fuel loads burn faster.
Dry air promotes a greater intensity fire than moist air. Plants become more flammable at a low humidity because they release their moisture more easily.
Fires pre-heat their fuel source through radiation and convection. As a consequence of these heat transfer effects, fires accelerate when travelling uphill and decelerate travelling downhill. The steepness of the slope plays an important role in the rate of fire spread. The speed of a fire front advancing will double with every 10 degree increase in slope so that on a 20 degree slope, its speed of advance is four times greater than on flat ground.
Bushfires can originate from both human activity and natural causes with lightning the predominant natural source, accounting for about half of all ignitions in Australia. Fires of human origin currently account for the remainder and are classified as accidental or deliberate. Fires lit deliberately can be the result of arson or designed to achieve a beneficial outcome but experience sudden adverse weather conditions which results in their uncontrollable spread.
Unfortunately deliberate and accidentally lit fires are more prevalent near populated areas and have a disproportionately higher risk of infrastructure impact. Arsonists place people and property at serious and unnecessary risk, particularly when igniting fires on extreme fire weather days.
More bushfires occur on Sunday than any other day
Bushfires is Australia's worst type of natural disaster.
In south east Australia, it is the most likely country in the world that has bushfires.
Can bushfires cause other major geological events to occur?
Yes ,they can
Bushfires cause climate change and volcanoes.
Bushfires in Australia mainly occur in Summer and Spring in Alice Springs, Kalgoorlie/ Perth and Victoria.
You will have seen at least one of these in your life.
These signs tell us how much risk of a fire there is going to be in that day.
Low-moderate means that there is a very low chance of a fire, and code red means a very,very high risk of a fire, and to be very alert.
Bushfires are part of the Australian landscape. They have been around for over 60 million years and they occur regularly in our weather system.
Black Saturday happened in Victoria, on the 7th -8th of February 2009.
Black Saturday resulted from some of the worst fire conditions ever recorded in Victoria. Record-high temperatures and strong winds after a season of intense drought set the bush alight across the state, causing widespread devastation.173 people and the destruction of more than 2100 homes.
Ash Wednesday started in Victoria and spread through to South Australia from the 16th -18th of February 1983.
Widespread drought, gale-force winds, high temperatures and low relative humidity set the scene for a series of fires across Victoria and south-eastern South Australia. Accidents and people deliberately lighting fires was the cause of most fires. which spread rapidly through scenic residential regions near Melbourne and Adelaide, resulting in the death of 75 people and the destruction of nearly 1900 homes.
Black Friday happened in Victoria on the 13th until the 20th of January 1939. Drought conditions and water shortages also preceded Black Friday, but the usual combination of high temperatures, strong winds, and low humidity finally triggered fires throughout bush communities near Melbourne. Well-meaning locals and farmers made the problem worse by trying to use controlled burns to protect themselves from disaster, only to see their good intentions help spread the flames. In all, 71 people were killed and 650 houses were destroyed.
Black Tuesday occurred in Tasmania on the 7th of February 1967.
An unusually abundant spring covered Tasmanian forest floors with litter, providing excess fuel for the bushfire season. Strong northerly winds and high temperatures joined to help fuel at least 80 different fires across southern Tasmania, which swept over the south-east coast of the state and came within 2km of central Hobart. The fires killed 62 people and razed almost 1300 homes.
Gippsland fires and Black Sunday in Victoria from the 1st of February until the 10th of March 1926.
Large areas of Gippsland caught fire, concluding in the Black Sunday fires on 14 February that killed 31 people in Warburton, near Melbourne. Over this time, a total of 60 people were killed.
Gippsland fires and Black Saturday
The weather conditions on the day were some of the worst bushfire weather conditions ever recorded. Temperatures reached 46 degrees celsius with winds in excess of 100km per hour. Leading up to the disastrous conditions was 2 months of extremely low rainfall and hot dry conditions.
Approximately 400 fires started during the day of the Black Saturday Bushfires.
The average speed of the Black Saturday Bushfires was 12km per hour, however in some circumstances the fires travelled up to 600m per 30 seconds. The radiant heat produced in some instances and was capable of killing people 400 meters away.
Spot fires, which are fires that start ahead of the main fire front from burning embers, were recorded 35 km ahead of the main fire fronts during the Black Saturday Bushfires.
The Black Saturday Bushfires killed 173 people, injured 414 people, destroyed 2,100 homes and displaced 7,562 people.
120 people were killed by a single fire in the Kinglake Area alone.
It is estimated the energy released by the Black Saturday Bushfires, was the equivalent of 1,500 Hiroshima atomic bombs. In total 1,100,000 acres were burnt.
On the morning of 7th of February, 3,582 firefighters were put on standby for the predicted weather conditions, with over 5,000 firefighters in total used to fight the fires. These firefighters came from over Australia, New Zealand and the United States.
Meteorologists study bushfires and other geological events to do with weather. They tell us when the bushfires are coming and other warnings.
Affects on living and nonliving things
Bushfires destroy many living things including...
Bushfires destroy many nonliving things including...
http://www.australiangeographic.com.au/topics/science-environment/2011/11/the-worst-bushfires-in-australias-history/ 9/11/14, Australian geographic, top 5 worst bushfires.
http://www.thefreedictionary.com/grassfire 9/11/14, the free dictionary, what is a grass fire.
http://www.bushfireeducation.vic.edu.au/for-educators/secondary/learning-about-bushfires/sec-learn-act4.html 11/11/14, bushfire education, bushfires.
http://dictionary.reference.com/browse/bushfires?s=t 14/11/14, dictionary, bushfires.
http://www.gtav.asn.au/CMS200/files/cms_files/Bushfires_final_txt_LR.pdf 16/11/14, bushfires, bushfire information.
http://www.readersdigest.com.au/my-story-in-the-path-of-a-bushfire 20/11/14, in the path of a bushfire, real life story of a bushfire.
Why do bushfires typically occur in Australia?
Bushfires occur in Australia because Australia has the exact climate and surroundings that a bushfire needs, dry,hot and winy temperatures.
How will scientific understanding help in the future with bushfires?
The Victorian State Government launched a fire prediction and early warning system based on Bushfire CRC research that will deliver detailed information on the spread of fires to help protect communities in the event of a bushfire.
How do bushfires affect the surface of the Earth?
Bushfires affect the surface of the Earth because the surface goes from green, shiny and lush to dark,charred and wrecked. It takes a long time for the areas damaged by the fires to turn green and nice again.