Wildfire Hazards Flashcards
Explain the natural causes of wildfires?
For a natural wildfire to occur and spread, two things are needed, an ignition source, most commonly lightning. Climate will affect the frequency of electrical storms, particularly in areas where there is hardly any rainfall. Fuel is also needed in sufficient quantities and it needs to be dry enough. Climate affects the frequency of drought and the vegetation that grows in the area.
Explain the human causes of wildfire?
increasingly fires are the result of human intervention, particularly those which occur in and around settlements. Such fires are started by falling power lines, carelessly discarded cigarettes, camp fires, barbecues and agricultural fires (controlled burning) which get out of hand. Greater access to wild areas by tourists has increased the dangers of fires from the reasons above.
What will affect the nature of the fire and why?
The nature of the fire will depend upon the types of plants involved, strength of winds, topography of the area in question and the behaviour of the fire itself. Once the vegetation has dried out, the nature of the fire will depend largely upon the wind, as the largest fires occur in dry windy weather with low humidity.
Ignition
Atmospheric conditions
Resources to burn
Using examples, explain the distribution of wildfires?
areas that are most susceptible are those with a Mediterranean and tropical wet/dry season (savanna ) climates. In Mediterranean climates (Southern Europe, California, parts of Australia), winter rainfall encourages vegetation growth but hot dry summers with occasional thunder storms, result in a fire hazard. A similar pattern occurs in Savanna regions (northern Florida, north eastern India + tropical regions of Africa and South America) although it is the summers that are wet and winters that are dry
Explain the primary impacts of a wildfire?
loss of crops, timber and livestock (huge impact on timber producing areas and the loss of trees will take many years to replace)
Loss of life
Loss of property (large numbers of people left homeless
Loss of wildlife
Release of toxic gas and particles (fire related air pollution)
Damage to soil structures and nutrient content
Explain the secondary impact of a wildfire?
evacuation: many people will flee from the affected area and often not be allowed back to the affected area for a long time. Emergency shelters / accommodation will have to be found along with food
Increased flood risk: in certain environments, where rain comes in heavy bursts, the loss of so much vegetation, and the consequent decrease in interception, can lead to increased flooding
What is vegetation management?
clearing areas between trees and other vegetation ahead of a wildfire event to create firebreaks, which help prevent the spread of the fire.
What is built environment management?
using fire resistant materials to build houses and extensions or outbuildings
Clearing flammable materials and vegetation within 10m of building to create fire resistant zones
What is computer modelling management?
this has been employed to understand and predict the fires behaviour. It evolves studying the ways in which fires behave to comprehend and predict fire behaviour
What is education management ?
in areas affected by fires.Governments often release guidance on how to prepare for such an event by familiarisation with evacuation routes, clearing flammable materials and vegetation within 10 m of buildings to create a fire resistance zones, creating a fireproof safe place at home for all important paper documents,putting together a bag essential for life away from home and signing up to be aware of fire warning systems produced.
What is warning systems management?
Signing up and being aware of fire warning systems produced (e.g. by the state of California and the federal weather service)
What is insurance management?
taking out of sufficient insurance to cover and replace everything that could be lost including the house itself
Out of the 3 risk managements designed to reduce the impact of wildfires, what is the strengths , weaknesses and rank of ecological restoration?
Ecological restoration
(Strengths?)
prescribed burning, low intensity and stops overpopulation of vegetation, allow decomposition
Low cost -> large scale
Sustainable as works with natural fires
Reduces fuel so minimises scale of fire
(Weaknesses)
lots of smoke in fire season
Public opposition in practise
Can lead to law suits
(Rank)
most effective
Low cost
Large scale
People can be persuaded
Makes fires less intense
Out of the 3 risk managements designed to reduce the impact of wildfires, what is the strengths , weaknesses and rank of thinning?
Strengths?)
hyper local fuel reduction in scale of fire
(Weaknesses?)
not effective in highest winds, when ultra dry (embers can travel long distances)
Unpopular as woods look scarse.
High cost + constant maintenance required
(Rank)
second most effective
Used if you can convince community of ecological restoration
Expensive
Not always effective
Out of the 3 risk managements designed to reduce the impact of wildfires, what is the strengths , weaknesses and rank of community preparedness?
(Strengths?)
orderly evacuation can save lives
Homeowners can reduce the risk around their homes
(Weaknesses?)
high ongoing budget required
Evacuations can cause panic
Not everyone will comply
Poorly communicated
People can be complacent
(Rank)
least effective , but still effective
Education can buy consensus for other management
Better prepared, reduce the risk of loss of life
