A wildfire, also known as a wildland fire, forest fire, vegetation fire, grass fire, peat fire, bushfire
(in Australasia), or hill fire, is an uncontrolled fire often occurring in wildland areas, but which can
also consume houses or agricultural resources. Common causes include lightning, human
carelessness, arson, volcano eruption, and pyroclastic cloud from active volcano. Heat waves,
droughts, and cyclical climate changes such as El Niño can also have a dramatic effect on the
risk of wildfires.
Wildfires are common in many places around the world, including forest areas of the United
States and Canada, where the climates are sufficiently moist to allow the growth of trees, but
feature extended dry, hot periods particularly in the Summer, fall, and in time of drought when
fallen branches, leaves, and other material can dry out and become highly flammable. Wildfires
are also common in grasslands and scrublands. Wildfires tend to be most common and severe
during years of drought and occur on days of strong winds. With extensive urbanization of
wildlands, these fires often involve destruction of suburban homes located in the wildland urban
interface, a zone of transition between developed areas and undeveloped wildland.
Wildfires often cause large-scale damage to private or public property, destroying many homes
and causing deaths, particularly when they have reached urban fringe communities.
Slash (small, rotten, misshapen, or otherwise undesirable wood discarded during logging) has
historically provided the fuel for devastating fires such as the fires in Michigan in the 19th century.
The aftermath of a wildfire can be as disastrous if not more so than the fire. A particularly
destructive fire burns away plants and trees that prevent erosion. If heavy rains occur after such
a fire, landslides, ash flows, and flash floods can occur. This can result in property damage
outside the immediate fire area, and can affect the water quality of drinking water, streams, rivers
and lakes.
In southern California, under the influence of Santa Ana winds, wildfires can move at tremendous
speeds, up to 40 miles (60 km) in a single day, consuming up to 1,000 acres (4 km²) per hour.
Dense clouds of burning embers push relentlessly ahead of the flames crossing firebreaks
without pause.
Propagation of the fire with a characteristic shape of a "pear"The powerful updraft caused by a
large wildfire will draw in air from surrounding areas. These self-generated winds can lead to a
phenomenon known as a firestorm.
On average, wildfires burn 4.3 million acres (17,000 km²) in the United States annually. In recent
years the federal government has spent $1 billion a year on fire suppression. 2002 was a record
year for fires with major fires in Arizona, California, Colorado, and Oregon.
People living in fire-prone areas typically take a variety of precautions, including building their
homes out of flame-resistant materials, reducing the amount of fuel near the home or property
(including firebreaks, their own miniature control lines, in effect), maintaining emergency supplies
and investing in their own firefighting equipment.
(in Australasia), or hill fire, is an uncontrolled fire often occurring in wildland areas, but which can
also consume houses or agricultural resources. Common causes include lightning, human
carelessness, arson, volcano eruption, and pyroclastic cloud from active volcano. Heat waves,
droughts, and cyclical climate changes such as El Niño can also have a dramatic effect on the
risk of wildfires.
Wildfires are common in many places around the world, including forest areas of the United
States and Canada, where the climates are sufficiently moist to allow the growth of trees, but
feature extended dry, hot periods particularly in the Summer, fall, and in time of drought when
fallen branches, leaves, and other material can dry out and become highly flammable. Wildfires
are also common in grasslands and scrublands. Wildfires tend to be most common and severe
during years of drought and occur on days of strong winds. With extensive urbanization of
wildlands, these fires often involve destruction of suburban homes located in the wildland urban
interface, a zone of transition between developed areas and undeveloped wildland.
Wildfires often cause large-scale damage to private or public property, destroying many homes
and causing deaths, particularly when they have reached urban fringe communities.
Slash (small, rotten, misshapen, or otherwise undesirable wood discarded during logging) has
historically provided the fuel for devastating fires such as the fires in Michigan in the 19th century.
The aftermath of a wildfire can be as disastrous if not more so than the fire. A particularly
destructive fire burns away plants and trees that prevent erosion. If heavy rains occur after such
a fire, landslides, ash flows, and flash floods can occur. This can result in property damage
outside the immediate fire area, and can affect the water quality of drinking water, streams, rivers
and lakes.
In southern California, under the influence of Santa Ana winds, wildfires can move at tremendous
speeds, up to 40 miles (60 km) in a single day, consuming up to 1,000 acres (4 km²) per hour.
Dense clouds of burning embers push relentlessly ahead of the flames crossing firebreaks
without pause.
Propagation of the fire with a characteristic shape of a "pear"The powerful updraft caused by a
large wildfire will draw in air from surrounding areas. These self-generated winds can lead to a
phenomenon known as a firestorm.
On average, wildfires burn 4.3 million acres (17,000 km²) in the United States annually. In recent
years the federal government has spent $1 billion a year on fire suppression. 2002 was a record
year for fires with major fires in Arizona, California, Colorado, and Oregon.
People living in fire-prone areas typically take a variety of precautions, including building their
homes out of flame-resistant materials, reducing the amount of fuel near the home or property
(including firebreaks, their own miniature control lines, in effect), maintaining emergency supplies
and investing in their own firefighting equipment.
Wildfires
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