Sixth generation fires or megafires: what they are and why they are so dangerous

Sixth generation fires are not common fires. These are extremely large, fast and destructive fires, which far exceed traditional extinguishing capabilities. They can move at high speed, change direction suddenly, and generate their own weather conditions, such as firestorms or intense winds, making them even more dangerous.

These types of fires usually appear in a context of climate change, high temperatures, prolonged droughts and accumulation of plant fuel (such as dry branches, leaves or bushes). All of this creates a perfect scenario for a fire to get out of control and grow without limits.

Here you can learn about Firestorms: what they are, how they form and risks.

How many generations of forest fires are there?

Currently, 6 generations of forest fires are recognized, classified according to their behavior, complexity and the control capacity of extinction services.

1st generation

• Simple and easy to control fires.
• They mainly affect light fuels (scrubs and grasses).
• They are turned off with basic terrestrial means.

2nd generation

• Faster and with greater intensity.
• They affect areas with denser vegetation (scrubland and young forests).
• They require more advanced aerial means and tactics.

3rd generation

• Greater energy and propagation.
• Influenced by the relief and local meteorology.
• They need more complex coordination and preventive strategies.

4th generation

• They occur in extreme weather conditions (heat waves and intense droughts).
• Difficult to contain; They can affect nearby urban areas.

5th generation

• High propagation speed, erratic behavior.
• Capable of creating secondary focuses at great distances (fire jumps).
• They impact urban and agricultural areas, with risk to the population.

6th generation

• Fires that exceed the extinguishing capacity.
• They feed themselves, they generate their own weather (pyrocumulus clouds and fire storms).
• They can last weeks and extend over thousands of hectares.

Therefore, when we talk about sixth generation fires, we are referring to the most extreme and dangerous level, closely linked to climate change and the accumulation of fuel in forests.

Sixth generation fires have a series of characteristics that clearly differentiate them from conventional forest fires:

• Large extension: These fires can cover thousands of hectares in a short time. They are not limited to a specific area, but can expand rapidly and affect vast natural, rural and even urban areas.
• High intensity and speed: The flames reach much higher temperatures than usual and advance at high speed. This makes extinguishing efforts extremely difficult and reduces the possibilities of action by emergency teams.
• Generation of extreme phenomena: They can generate fire storms, columns of smoke that create lightning, and erratic winds that rekindle flames in multiple directions. In some cases, they form pyrocumulus, clouds that are born from the heat of the fire and can produce their own rain or even lightning that causes new outbreaks.
• Unpredictable behavior: Its evolution is very difficult to anticipate. They can change direction without warning, cross roads, rivers or firebreaks, and jump long distances using incandescent particles carried by the wind.
• Capacity to affect inhabited areas: Not limited to remote forest areas. These fires advance towards urban centers, putting entire populations, homes and infrastructure at risk.
• Long duration: Unlike other fires that can be controlled in hours or days, megafires can remain active for weeks or even months, especially if adverse weather conditions such as extreme heat, drought and constant wind occur.

Climate change is not only altering the global climate, it is also creating much more conducive conditions for wildfires to become larger, more intense and more difficult to control.

• Heat waves are becoming more frequent, longer and more intense. High temperatures dry out vegetation and reduce soil moisture, creating a perfect environment for any spark to turn into an uncontrolled fire.
• In many regions, rainfall is increasingly scarce or poorly distributed. This causes a buildup of dry material (such as branches, bushes, and leaves), which acts as highly flammable fuel.
• Although some areas continue to receive rain, they often do so in the form of intense and specific storms that fail to moisten the land in a sustainable manner. This means that vegetation grows quickly during rains, but then dries out and becomes fuel for fires.
• Climate change also alters wind patterns. Stronger and changing winds not only help spread the flames, but make it difficult to predict their behavior, putting both emergency teams and the population in danger.

Sixth generation fires represent an unprecedented threat due to their strength, behavior and destructive capacity because they grow so quickly and with such intensity that traditional means of extinction such as planes, helicopters or ground brigades become insufficient. In many cases, you can only act on the edges or wait for weather conditions to change.

They are also so dangerous because they can quickly reach towns, housing estates and cities. They generate extreme phenomena such as gusts of wind, lightning or columns of smoke that modify the environment. These factors cause the fire to suddenly change direction, spread through the air over long distances, and re-ignite in already controlled locations.

In this other post we talk about the consequences of forest fires.

Although these types of extreme fires were more common in countries such as Australia, the United States or Canada, in recent years Spain has also begun to suffer sixth generation fires, especially due to rising temperatures, longer heat waves and the accumulation of dry vegetation in rural and forest areas.

These are some of the most notable examples in Spanish territory:

Navalacruz Fire (Ávila, 2021)

Considered one of the first sixth generation fires in Spain. It started with a mechanical failure in a car and spread quickly due to extreme heat and wind. It devastated more than 22,000 hectares and forced more than 1,000 people to evacuate. Their behavior was very aggressive and overwhelmed the extinguishing means available in the area.

Sierra Bermeja Fire (Málaga, 2021)

Another emblematic case. It burned nearly 10,000 hectares and forced the evacuation of about 2,600 people. The most worrying thing was that the fire developed a pyrocumulus, that is, a cloud created by the heat of the fire itself that fuels its expansion. This phenomenon marked a before and after in the history of forest fires in Spain.

Fire in Ateca (Zaragoza, 2022)

Originated by reforestation work with machinery in the heat of the heat wave, this fire grew rapidly to affect more than 14,000 hectares. Its intensity, speed of spread and proximity to inhabited areas forced thousands of people to evacuate. It was classified by experts as a fire of extreme behavior.

Although it is very complex to prevent them, there are some key measures such as:

• Active forest management: Clean, clear and maintain forests to reduce this flammable load, especially in areas close to towns and homes.
• Recover the rural environment: The abandonment of the fields and the depopulation of the rural world have contributed to the increase in risk. Traditional activities such as agriculture, extensive livestock farming or collecting firewood helped keep the landscape clean and manageable.
• Design fire-resistant landscapes: Firebreak strips can be created, crops and open spaces maintained between forest masses, and ensuring that urban environments are not surrounded by uncontrolled vegetation.
• Education and citizen awareness: A large part of fires have human origin: poorly extinguished barbecues, cigarette butts, agricultural burning or negligence. Informing and training the population about risk, especially in times of high danger, can prevent many catastrophes.

Here we tell you more about How to prevent forest fires.

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