Wildfire (natural disasters)

Event in historical context

Countries affected

The earthquake and resulting tsunami affected many countries in Southeast Asia and beyond, including Indonesia, Sri Lanka, India, Thailand, the Maldives, Somalia, Myanmar, Malaysia, Seychelles and others. Many other countries, especially Australia and those in Europe, had large numbers of citizens traveling in the region on holiday. Both Sweden and Germany lost over 500 citizens each in the disaster.

This earthquake was the fourth most powerful earthquake recorded since 1900, and the confirmed death toll is just under 200,000 due to the ensuing tsunami. The deadliest earthquakes since 1900 were the Tangshan, China earthquake of 1976, in The 2004 tsunami is the deadliest in recorded history. Prior to 2004, the deadliest recorded tsunami in the Pacific Ocean was in 1782, when 40,000 people were killed by a tsunami in the South China Sea.^[48] The tsunami created by the 1883 eruption of Krakatoa is thought to have resulted in 36,000 deaths. The most deadly tsunami between 1900 and 2004 occurred in 1908 in Messina, Italy, on the Mediterranean Sea, where the earthquake and tsunami killed 70,000. The most deadly tsunami in the Atlantic Ocean resulted from the 1755 Lisbon earthquake, which, combined with the toll from the actual earthquake and resulting fires, killed over 100,000.

The 2004 earthquake and tsunami combined have been described as the deadliest natural disaster since either the 1976 Tangshan earthquake or the 1970 Bhola cyclone.

A wildfire, also known as a wildland fire, forest fire, brush fire, vegetation fire, grass fire, peat fire, 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, slash-and-burn farming (относящийся к подсечно-огневому земледелию), arson, and underground coal fire. Heat waves, droughts, and cyclical climate changes can also dramatically increase the risk of wildfires.

Background. Wildfires are very common in many places around the world, including much of the vegetated areas of Australia, in the Western Cape of South Africa, and the forested areas of the United States and Canada. The climates of these areas are sufficiently moist to allow the growth of trees, but feature extended dry, hot periods. Fires are particularly prevalent in the summer and autumn, and during droughts when fallen branches, leaves, grasses and scrub can dry out and become highly flammable. This is especially the case in areas where eucalypts are prevalent, as the oil of these species is extremely flammable. News reports have suggested that global warming has been increasing the intensity and frequency of droughts in many areas, creating more intense and frequent wildfires.

Behavior. The evaporation of water in plants is balanced by water absorbed from the soil. When this balance is not maintained, plants dry out and when under this kind of stress they release the flammable gas ethylene. A consequence of a long hot and dry period is therefore that the air contains flammable essences and plants are drier and highly flammable.

Charred landscape following a crown fire in the North Cascades

A massive forest fire

The propagation of the fire has three mechanisms:

Crawling fire: the fire spreads via low level vegetation (e.g., bushes)

Crown fire: a fire that “crowns” (spreads to the top branches of trees) can spread at an incredible pace through the top of a forest. Crown fires can be extremely dangerous to all inhabitants underneath, as they may spread faster than they can be outrun, particularly on windy days.

Jumping fire and spotting fire: burning branches and leaves are carried by the wind and start distant fires; the fire can thus “jump” over a road, river, or even a firebreak.

Prevention. 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), and investing in their own firefighting equipment. Rural farming communities are often threatened directly by wildfire.

Fire suppression. Wildland fire suppression is a unique aspect of firefighting. Most fire-prone areas have large firefighter services to help control bushfires. As well as the water-spraying fire apparatus most commonly used in urban firefighting, bushfire services use a variety of alternative techniques. Typically, forest fire fighting organizations will use large crews of 20 or more people who travel in trucks to the fire. These crews use heavier equipment to construct firebreaks, and are the mainstay of most firefighting efforts. Other personnel are organized into fast attack teams typically consisting of 5–8 people. They use portable pumps to douse small fires and chainsaws to construct firebreaks or helicopter landing pads if more resources are required. Hand tools are commonly used to construct firebreaks and remove fuels around the perimeter of the fire to halt its spread, including shovels, rakes. In the eastern United States, portable leaf blowers are sometimes used. In the western United States, large fires often become extended campaigns, and temporary fire camps are constructed to provide food, showers, and rest to fire crews. These large fires are often handled by 20 person hand crews, sometimes known as hotshot crews, specially organized to travel to large fires.

A helicopter dips its bucket into a pool before returning to drop the water on a wildfire outside of Naples, Italy.

The Old Fire burning in the San Bernardino Mountains (image taken from the International Space Station)

Plowing a fire lane in advance of a forest wildfire, Georgetown, South Carolina

Дата добавления: 2014-12-27