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Shortly after daybreak, the landscape is still black and beige.
Along the road, bare, charred or semi-desert soils, with the exception of a few yellowish clumps bleached by the morning frost.
Heaps of logs dot the paths.
Six months after the fires of 2022, South Gironde is still scarred.
In one month, 32,000 hectares went up in smoke.
And the smoke is still there.
You might think winter is well established, but despite the low temperature in February, thick fumaroles still emanate from the frozen ground in places.
Since the fires, the departmental domain of Hostens is still burning, but slowly.
These columns of smoke are the consequence of an underground combustion of lignite - a kind of coal - which caught fire last summer and "
nibbles
" from the ground around the lakes of the area.
The surroundings of the Hostens lakes still bear the scars of this summer's fires.
Jean Cittone / Le Figaro
The Domaine d'Hostens remains a veritable natural setting, with its 600 hectares located in the heart of the Landes de Gascogne regional natural park.
It now consists of five large lakes and several wetlands.
Although this wooded expanse has the appearance of a natural area, the estate was once an industrial site.
The lakes are actually old open pit excavations of lignite, which fed the city's power station.
Read also“We came to say goodbye”: the beginning of the destruction of the Signal in Soulac-sur-Mer
Active from 1932, “
the Hostens power station provided 2% of national electricity needs
” in the 1950s, explains Hostensois Gwénolé Belbéoc'h in the journal
Geologists
.
With the exhaustion of the deposit, the exploitation ended up being dismantled and its decommissioning took place in 1964
. reminiscent of the fossil species that make up the lignites of Hostens
", explains Gwénolé Belbéoc'h.
Since then, the estate has been home to "
an extraordinary plant diversity
" and constitutes a field of study "
particularly interesting to study to understand how nature colonizes a former industrial site
”.
The banks of Lake Bousquey are still crossed by fumaroles.
Jean Cittone / Le Figaro
"It's a question mark for everyone"
Since his departure this summer, the combustion of lignite has been closely monitored by the departmental council and the departmental fire and rescue service (SDIS) of Gironde.
Because it is the first time that a fire has taken place around these artificial lakes, in an area that is a member of the Natura 2000 network. The fire spreads very slowly, as lignite does not need a large quantity of oxygen. to burn, but "
at any time in this afforestation, trees can catch fire
", explains Franck Uteau, engineer in charge of the environment mission within the Gironde department.
“
Collapses took place at the edges of the banks, because of the roots of the trees which burned
”, explains the engineer.
This Thursday, he went to the site with two members of the surveying company Parallèle 45. By taking readings with the thermal camera of a drone, they are trying to determine if the fire is spreading underground.
Several dozen "
thermal anomalies
" have been recorded in recent months.
On the images taken by drone, red dots reveal temperatures sometimes exceeding 300 degrees on the ground.
“
In the literature, it is coal that burns for so long, not lignite
,” explains Franck Uteau, who has not found any other examples of a lignite mine that burns continuously.
In the United States, the locality of Centralia, for example, has become a ghost town since the start of a fire in a coal mine in 1962, because sixty years later, the fire continues to spread underground.
In Hostens, this underground hydrocarbon fire is a novelty.
"
It's a question mark for everyone, but the advantage we have is that it burns slowly
".
The drone made it possible to record ground temperatures sometimes exceeding 300 degrees around Lake Bousquey.
Jean Cittone / Le Figaro
"
The interest of thermal cameras is that they allow us to see things invisible to the naked eye
", specifies Benjamin Sadier, head of the topography division of Parallèle 45. The use of the drone makes it possible, for example, to detect hot spots which do not emit smoke and the overflight makes it possible to avoid damaging the area by traversing it on foot.
“
Today, it is a question of making a diagnosis, because we do not really know if the fire is spreading or how it is spreading
”, explains this doctor in geomorphology and specialist in 3D modeling.
All attempts to extinguish the fire failed
Despite the research carried out since last year, great uncertainties still hang over the Hostens estate.
“
Sometimes we cut down a tree and the fire starts up again underneath, because it just lacked a little more oxygen
,” explains Franck Uteau.
And “
despite many waterings, it still burns
”.
The department was counting on heavy rains and a rise in the waters of the various lakes which could have made it possible to extinguish the fire.
So far, the winter has been too dry and attempts to extinguish these hotspots have all failed.
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If the disaster scenarios are not considered for the time being, the question arises of the total extension of this lignite deposit, which extends in part under the municipality of Hostens.
"
This risk exists, but the closest hotspots would be the most dangerous
."
However, those who have been mapped for the moment "
are still far from the village
" specifies the engineer.
The mapping work carried out, hoping that the fires will not start again soon around the lakes, makes it possible to "
take the time to act as best as
possible ", by studying the terrain and the possibilities of acting to limit the spread of the fire.
Lignite in Hostens, yesterday and today
Go to slideshow (6)
Within a week, the analysis of the images taken from the drone will give the departmental council an overview of the evolution of the thermal anomalies to "
determine whether there is progress or not
".
"
What would be interesting is that certain hot spots have disappeared
", hopes Franck Uteau, but conversely, "
it would be worrying if new ones appeared
".
This work is carried out in collaboration with the Bureau of Geological and Mining Research (BRGM).
On site this Thursday, some firefighters also show their interest in this work of retrieving information on the ground, in order to allow the department and the prefecture to take the necessary decisions.
The men of the fire were also counting on abundant rains this winter.
During the fires, the lakes of Hostens had also been largely used to supply the fire engines, in order to put out the fires around the estate.
Read alsoGironde: 40% of fire trucks still under repair after this summer's fires
For the moment, Jean-Louis Dartiailh, mayor of Hostens, is not overly worried about this situation, because the estate is closed and the inhabitants warned of the risks of collapse.
The Hostensois "
simply await the reopening, because it was their walking circuit
".
For the city councilor, it is above all a question of "
saving as much as possible
" of the vegetation affected by the flames.
Pointing to pines with burnt trunks but whose tops remain green, the mayor fervently hopes that they "will
leave again in the spring
".
But until then, no one is able to say if Hostens' basement will have finished burning.
For the moment, the departmental domain is completely closed to the public.
Jean Cittone / Le Figaro