Explained: How and why wildfires are scorching Europe

Southwest Europe continues to battle devastating wildfires with sweltering temperatures and extreme heat forcing thousands out of their homes and sending holidaymakers scurrying for safety.

Britain and France went on heatwave alert on Monday bracing for record temperatures as southwest Europe wilted under a scorching sun and ferocious wildfires devoured more forests.

This after Portugal and Spain and France saw armies of firefighters battle blazes and Irish forecasters predicting a taste of blistering Mediterranean-style summer temperatures.

But what are wildfires? How do they occur? Let’s take a closer look:

What are wildfires?

The United Nations defines a wildfire,(also known as forest, bush or vegetation fire) as any uncontrolled and non-prescribed combustion or burning of plants in a natural setting such as a forest, grassland, brush land or tundra which consumes the natural fuels and spreads based on environmental conditions such as wind and topography.

As per the UN, there are three basic types of wildfires:

• Crown fires burn trees up their entire length to the top. These are the most intense and dangerous wildland fires.
• Surface fires burn only surface litter and duff. These are the easiest fires to put out and cause the least damage to the forest.
• Ground fires (sometimes called underground or subsurface fires) occur in deep accumulations of humus, peat and similar dead vegetation that become dry enough to burn. These fires move very slowly, but can become difficult to fully put out, or suppress.

How do they occur?

They can occur due to human actions such as land clearing, campfires, cigarettes and even arson or environment factors such as the sun, hot winds, dry weather, extreme drought or lightning (in rare instances).

Though the US’ Environmental Protection Agency classify wildfires as natural disasters, only 10 to 15 percent of them occur due to nature, The result from human causes, including unattended camp and debris fires, discarded cigarettes, and arson.

As per National Geographic, there are three conditions needed for a wildfire: fuel, oxygen, and a heat source. Fuel is any flammable material surrounding a fire, including trees, grasses, brush, even homes. The greater an area's fuel load, the more intense the fire.

Air supplies the oxygen a fire needs to burn, while heat sources help spark the wildfire and bring fuel to temperatures hot enough to ignite.

Lightning, burning campfires or cigarettes, hot winds, and even the sun can all provide sufficient heat to spark a wildfire, as per the report.

How they are stopped?

As per National Geographic, firefighters battle blazes by depriving them of one or more of the fire triangle fundamentals.

A traditional method is to douse fires with water and spray fire retardants. Firefighters also sometimes work in teams, often called hotshots, to clear vegetation from the land around a fire to contain and eventually starve it of fuel. The resulting tracts of land are called firebreaks.

Then there’s controlled burning or backfires – literally fighting fire with fire.

These remove undergrowth, brush, and litter from a forest, which deprives wildfire of a  fuel source.

How dangerous is wildfire smoke?

As per Indian Express, wildfire smoke, particularly PM 2.5, can affect the respiratory and cardiovascular systems of human beings. For those already suffering from cardiovascular or respiratory illnesses, there is a risk of flare-ups.

What’s happening in Europe?

This is the second heatwave to engulf parts of southwest Europe in weeks. Scientists blame climate change and predict more frequent and intense episodes of extreme weather such as heatwaves and drought.

In its annual Frontier report this year, the United Nations Environment Programme (UNEP) said: “The trends towards more dangerous fire-weather conditions are likely to increase due to rising concentrations of atmospheric greenhouse gases and the attendant escalation of wildfire risk factors.”

Spanish authorities reported around 20 wildfires still raging out of control in different parts of the country from the south to Galicia in the far northwest, where blazes have destroyed around 4,500 hectares of land.

The fires have already killed several emergency personnel since last week, most recently a fireman who died late on Sunday while battling a blaze in northwestern Spain.

In France, the situation deteriorated in the southwestern Gironde region where firefighters were fighting to control forest blazes that have devoured nearly 11,000 hectares (27,000 acres) since Tuesday.

'A heat apocalypse'

The wildfires in France forced more than 16,000 people -- residents and tourists combined -- to decamp. Seven emergency shelters have been set up for evacuees.

France's interior ministry announced it would send an extra three firefighting planes, 200 firefighters and more trucks.

Meteo France forecast temperatures of up to 40 degrees Celsius (104 degrees Fahrenheit) in parts of southern France on Sunday, with new heat records expected on Monday.

"In some southwestern areas, it will be a heat apocalypse," meteorologist Francois Gourand told AFP.

France placed 15 departments, mainly down its western seaboard, on red alert -- the highest on the scale -- on Sunday while 51 were on orange high alert.

The chapel of a historic hospital in the southeastern city of Lyon, Grand Hotel Dieu, offered refuge to tourists on Sunday including Jean-Marc, 51, who was visiting from Alsace.

"We came back to admire the place, but we can't leave, it's too hot outside. We say a prayer before the fire!" he quipped.

French cyclist Mikael Cherel, taking part in the Tour de France's 15th stage between Rodez and Carcassonne in southern France on Sunday, described "very, very difficult conditions".

"I've never known such a hot day on a bike. It really was no picnic."

Deaths

In Spain, firefighters managed to stabilise a wildfire that ravaged 2,000 hectares of woods and bushes in the southern region of Andalusia, regional leader Juan Manuel Moreno said.

The blaze started on Friday in the Mijas mountain range inland from the southern coastal city of Malaga and it spurred the evacuation of about 3,000 people.

Around 2,000 people had since returned home and now that the blaze has stabilised, Moreno said the remaining evacuees may do the same.

A fireman died from burns on Sunday while battling a blaze in Spain's northwestern province of Zamora, the regional government said.

Spanish Prime Minister Pedro Sanchez expressed his "condolences and affection" to the man's family and colleagues.

"There are no words to express thanks to those who fight fires without rest for their immense work. RIP," he added in a tweet.

Sanchez is due to visit the hard-hit eastern region of Extremadura on Monday where various fires have been raging for days.

The fireman's death comes after a pilot was killed last week when his plane crashed in northern Portugal, and two crew members died in Greece when their helicopter fell into the sea.

The extreme heat also claimed the lives of two men in Spain over the weekend.

A 50-year-old man in Torrejon de Ardoz just outside of Madrid died on Sunday after suffering heat stroke while out for a walk, local emergency services said.

And on Saturday, a 60-year-old street cleaner in Madrid died after suffering heat stroke while working the previous day.

In Portugal, almost the entire country remained on high alert for wildfires despite a slight drop in temperatures, after hitting 47C -- a record for the month of July -- on Thursday.

Only one major fire was burning on Sunday in the north.

The fires have killed two, injured around 60 and destroyed between 12,000 and 15,000 hectares of land in Portugal.

‘Risk to life' in UK

In the United Kingdom, the weather office issued a first-ever "red" warning for extreme heat, cautioning there was a "risk to life".

The Met Office said temperatures in southern England could exceed 40C on Monday or Tuesday for the first time, leading some schools to say they would stay closed next week.

Organisers of a four-day march in the Netherlands cancelled the first day of the mass event due to start on Tuesday because of extreme heat.

The mercury is set to reach 38C in parts of the Netherlands on Tuesday.

With inputs from agencies

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