Wildfires Flashcards
What are wildfires?
Wildfires are uncontrolled fires that destroy forests, grassland, and other areas of vegetation. They usually occur in rural areas, but if they reach inhabited areas, they will destroy agricultural land and settlements.
What are the three types of wildfires?
Ground fire- where the ground itself burns. It is a slow, smoldering fire with no flame and little smoke.
Surface fire- where leaf litter and low lying vegetation burn. Fire can be low or high intensity.
Crown fire- where fire moves rapidly through the canopy (the top layer of vegetation). Fires are likely to be intense and fast-moving.
What are certain conditions that favor intense wildfires?
Vegetation Type:
> Thick undergrowth or closely spaced trees allow the fire to travel easily.
> Some trees, such as eucalyptus and pine, contain a lot of oil and so burn very easily.
> Eucalyptus trees shed strips of their bark which helps the fire to spread quickly.
Fuel characteristics:
> Fine, dry material catches fire and burns most easily.
> Large amounts of fuel that form a continuous cover will help the fire burn for longer and spread.
Climate and recent weather:
> Rainfall must be sufficient for vegetation to grow, so there’s plenty of fuel.
> Warm weather causes vegetation to dry up, so it’s more flammable.
> Strong winds provide more oxygen to help the fire burn and spread during embers.
Fire behavior:
> Fire burns in different ways e.g. creeping fire moves across the ground surface fairly slowly, whereas a running fire spreads more rapidly and is more intense.
> Fires can throw out burning debris that help the fire spread and become more intense.
How do wildfires have natural causes?
> Lightning is particularly likely to start a fire in areas without much rain.
Volcanic eruptions can produce very hot lava, ash or gas, which can start fires.
How do wildfires have human causes?
> Most fires are started by people. This can be accidental e.g. by dropping cigarettes, allowing barbeques and campfires to get out of control.
Fireworks or sparks from machinery land in vulnerable areas.
Fires can also be started on purpose (arson)
How do wildfires have an impact socially, economically, environmentally, and politically?
Social:
> People may be killed or injured if they do not evacuate in time.
> Homes are destroyed, so people may be left homeless.
> Wildfires can destroy power lines and damage reservoirs, leaving people without electricity or clean water.
> Wildfires can cause health problems from all the ash being breathed in.
Economic:
> Wildfires destroy businesses, leading to the loss of jobs and income.
> The cost of fighting wildfires is huge.
> Wildfires may discourage tourists, reducing income.
Environmental:
> Habitats are destroyed. Some species may not return to the area after the fire, changing the ecosystem
> Soils are damaged as the fire removes organic matter.
> Smoke causes air pollution, and water sources can be contaminated with ash.
Political:
> Governments can face criticism when wildfires have severe impacts.
> Governments may have to change their forest management practices to reduce the risk of wildfire e.g. by clearing vegetation to limit fuel.
What responses are made to reduce the impacts of wildfires?
1) Mitigation strategies aim to reduce the severity of the wildfire impacts.
2) Short-term responses:
- Diverging the fires away from settlements.
- Evacuating people at risk
-Spraying water onto roofs or houses.
3) Long-term responses
- Prevention- involving public education about the risks.
> Preparedness- Households have an emergency plan and emergency supplies of food, water, and medicine.
>Adaption- Using nonflammable building materials and creating fire breaks.
