What are wildfires? Why are they becoming more frequent and intense across the world?

A California wildfire that closed nearly 200 square miles of forest forced evacuations across state lines into Nevada recently as winds and scorching, dry weather drove flames forward through trees and brush.

The Beckwourth Complex – which began as two lightning-caused fires in Plumas National Forest – was intense. Hot rising air formed a gigantic, smoky pyrocumulus cloud that reached thousands of feet high and created its own lightning.

In north-central Arizona, increased humidity slowed a big wildfire that posed a threat to the rural community of Crown King.

Elsewhere, Cyprus saw one of the worse wildfires since the Republic of Cyprus was established in 1960. Wildfires destroyed 50 homes, damaged power lines and forced the evacuation of 10 villages. The blaze ripped through mountain forests and farmland, killing four people and destroying scores of homes.

Water-bombing planes from Greece and Israel and British aircraft from bases on the Mediterranean island helped douse the huge fire, which blackened 55 square kilometres (21 square miles) of the Troodos Mountains.

Climate change is considered a “key driver’ of a trend that is creating “longer and more intense dry seasons that increase moisture stress on vegetation and make forests more susceptible to severe wildfire,” the California Department of Forestry and Fire Protection said.

What is a wildfire?

An uncontrolled fire in an area of combustible vegetation which spreads quickly, wiping out large areas of land is called a wildfire. A wildfire can also be termed a forest fire, a grass fire, a peat fire or a bush fire, depending on the type of vegetation present in the area.

What causes wildfires?

Wildfires are common in Australia, Southeast Asia, southern Africa, Western Cape of South Africa, the forested areas of the United States and Canada, and the Mediterranean Basin. During summer, when there is no rain for months, the forests become littered with dry leaves and twigs, which could be ignited by the slightest spark.

Natural causes: Lightning is the most common cause of wildfire. There are three conditions for a forest fire to spread -fuel, oxygen and a heat source. In the forest, anything that is flammable is a fuel. This includes tall, dry grass, bushes and trees. High temperature, drought and dry vegetation are a perfect combination for igniting a forest fire.

Man-made disaster: Human neglect such as downed powerlines, sparks from tools or forest machinery, abandoned campfires and discarded cigarette butts can spark fires. People also tend to clear forests by setting them on fire to pave way for cultivation. Sometimes they set fire to scare away wild animals.

How is a forest fire put out?

Traditional extinguishing methods include water dousing and spraying of fire retardants from aircraft. To limit the spread of a fire, firefighters remove ground litter and bush.

What is a heatwave?

A heatwave is a period of prolonged abnormally high surface temperatures relative to those normally expected. Classifying a heatwave varies from country to country. The World Meteorological Organisation (WMO) defines heatwaves as five or more consecutive days during which the daily maximum temperature surpasses the average maximum temperature by 5°C or more.

What is the link between climate change and forest fires?

  • Climate change has created conditions conducive to forest fires. Long summer, drought, and dry air and vegetation make forests more susceptible to severe wildfire.
  • Climate change has led to frequent heatwaves across the globe. Hotter temperatures, again, mean parched land.
  • Climate change has also lengthened the fire season in many parts of the world.

Why does California experience forest fires quite often?

California’s climate: Wildfires are a natural part of its landscape. California has two distinct fire seasons- one that runs from June through September and another from October through April. While the first one is driven by a combination of warmer and drier weather, the second one is driven by dry winds which make wildfires spread rapidly and cover large areas.

Longer fire season: In the recent past, the fire season in California has been starting earlier and ending later. The length of the season is estimated to have increased by 75 days. Beetle infestation: Prolonged drought conditions leave behind a landscape of dead trees, which lead to infestation by bark-eating pests such as the mountain pine beetle. Outbreaks of pests weaken and kill trees. Beetle-killed trees are at a higher risk of fire.

Warmer weather: Heatwave is a major contributor to forest fires in California.

Picture Credit : Google

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