2. Elements of Fire
The fire triangle has three elements:
Heat
Oxygen
Fuel
Bushfire Example
For Bushfires fuel is provided by dry or dead trees and
grasses. More fuel is available in undergrowth as a result of
dry weather conditions.
Oxygen is in the natural. Trees and branches lay on each
other when they fall to the ground which means there is
space between them and as a result, air (and therefore
oxygen) is able to move into the fire.
Heat which starts bushfires comes from both natural and
man-made sources. For example lightning strikes or
campfires which are not properly extinguished.
3. Bushfire Process
Step 1. Ground and plants become very dry in times of
hot weather and drought.
Step 2. A spark is created [deliberately lit, glass lying
around in the foliage being heated up by the sun, spark
from power tools or machinery, lightning, campfires not
being extinguished properly] and starts a small fire.
Step 3. If there is wind, fire starts to move in that
direction or on steep hills, then the fire moves up the
side of the hill.
Step 4. If the fire is not contained quickly the fire gets
out of control and becomes a threat to large areas of
land and property.
4. Fire Danger Ratings
Fire Danger Ratings are forecast by the Bureau of Meteorology due
to the wind, temperature, humidity and rainfall conditions. Also
considered is the level of fuel available to burn which is determined
from the previous weather conditions.
Fire Danger Ratings indicate the danger level if a fire was to occur
and the level of difficulty of putting the fire out.
To minimise the potential for a fire occurring during Extreme or
Catastrophic conditions a Total Fire Ban may be announced which
means that people are not allowed to light fires or do a range of
other activities that may cause a spark.
5. Fire-Fighting Tools
A wide range of fire-fighting tools are used to fight bushfires. Some of these
tools include things to prevent bushfires such as fire danger ratings and total
fire bans. Announcements on TV and radio during weather forecasts for bush-
fire conditions and risks.
Detection and early warning methods are also used to warn of bushfires
including infra-red imaging of smouldering trees, the use of fire spotting towers
and lightning strike detector systems.
Once a bushfire has started, normal fire-fighting equipment such as trucks, high
preasure hoses, water pumps, masks/oxygen tanks, heat resistant clothes,
axes, water bombing aircraft are used to fight the fire.
Communication tools are also important to reduce the impact of bushfires,
including radios, mobile phones, the internet and Twitter to provide
announcements to the public.
6. Environmental Impacts
Many species of wildlife and vegetation are affected by
bushfires. Animals may be injured or killed and
vegetation destroyed. However some vegetation requires
bushfires to enable seeds to be released and new growth
in forests results after bushfires.
Bushfires contribute to Global Warming by releasing
large quantities of CO2 [carbon dioxide] into the
atmosphere.
7. Social Impacts
Many people are affected by
bushfires as a result of houses
being built on the edge of forest
areas.
Injuries to people and loss of life
can result from bushfires which
has a large impact on families
and friends.
However some positive things
come from events such as
bushfires, because people
donate food, clothes and toys to
people who have lost their
homes. Helping each other
builds community spirit.
8. Economic Impacts
Some of the economic impacts include loss of homes,
cars, etc and for farmers the loss of livestock and crops
has a large cost.
Damage to power lines, water supplies, roads, schools,
shops and businesses in towns by bushfire cost a lot to
rebuild and some people will move away from an area
which has had a bushfire.
A lot of money, work and time is needed to rebuild a
town and to get a community back to the way it was
before the bushfire.
9. Comparison with Volcanoes
Volcano
Ash Cloud
Acidic Water
Fast Moving
Unpredictable
Limited to particular areas
of the world
Affects low-lying areas
around the volcano
Usually happen with
earthquakes
Evacuation is possible if
enough warning time is
given
No defences against lava-
flow
Bushfire
Ash Cloud
Fast Moving
Unpredictable
Can happen anywhere
particularly in Australia
Can move easily and
quickly over terrain
Evacuation is possible if
enough warning time is
given
Damage may be reduced
using fire-fighting
equipment and bush-fire
prevention
