Satellite Images Reveal Origin of Belgium’s Largest Fire

An investigation using Copernicus Sentinel-2 satellite imagery has identified the precise origin of the Hautes Fagnes fire—the largest wildfire ever recorded in Belgium—shedding new light on how a routine mowing operation may have sparked the blaze that consumed more than 3,366 hectares of protected nature reserve. The findings, published by RTBF, also reveal that no explicit mowing ban was in effect in Liege province, despite elevated fire risk warnings from the Celex monitoring cell.

The fire began on Friday, 14 August 2026, around 13:00 near the Fagne des Deux-Series, close to the Croix Mockel area in the municipality of Baelen. It ultimately devastated approximately 75 percent of the Hautes Fagnes nature reserve—an area roughly the size of the city of Verviers—threatening the iconic black grouse population and the peat bogs that serve as critical carbon sinks.

Satellite Analysis Identifies Fire’s Origin

RTBF’s investigation team combined Copernicus Sentinel-2 satellite imagery with amateur video captured by parachutists flying over the area to pinpoint the fire’s starting location: approximately 300 meters west of Croix Mockel, along a path called the “allée du grand fossé.”

Pierre Chouak, a parachute instructor who filmed the fire’s beginning from the air, described what he witnessed. “We weren’t that high yet, so we could still see clearly,” he told RTBF. “We really see the start of the fire, which isn’t very big yet, but we can already see the smoke plume, which is already quite significant. We didn’t see any walkers along the path, I didn’t see any vehicle there, no one.”

The satellite imagery revealed that the parcel where the fire started had been partially mowed between 10 and 14 August, confirming that mowing work was underway in the days immediately preceding the blaze.

The Mowing Machine Hypothesis

The Liege public prosecutor’s office opened a judicial investigation for involuntary arson on 25 August, with the primary hypothesis focusing on an agricultural machine performing mowing work on the parcel where the fire originated. According to RTBF’s reporting, the mowing machine began work on Thursday, 13 August, continued through the day, and resumed Friday morning—leaving the zone before 10:00, several hours before the fire was detected.

Nicolas Yernaux, spokesperson for the Service public de Wallonie (SPW), confirmed that mowing operations were underway at the identified location. “Mowing is a technique that has been carried out by the DNF for many years on the Hautes-Fagnes plateau to restore biodiversity,” he said. “It will indeed be up to the investigation to determine whether this hypothesis of the agricultural machine is confirmed or disproven, but there was indeed an agricultural machine working at that location.”

The mowing work was subcontracted by the Walloon Region to a private company, which declined to comment when contacted by RTBF. The work involves gyrobroyeurs—rotary mowers attached to tractors with cutting hammers spinning at approximately 2,000 revolutions per minute. Jean-Luc Evrard, director general of a company that sells and repairs these machines, explained how they can generate sparks when they contact stones, potentially igniting dry vegetation.

“It’s scandalous to have commissioned a contractor with such a machine in well-known drought conditions,” Evrard said. “Activity with mechanized machines on such dry sites was not at all recommended.”

A Question of Missing Restrictions

The investigation also highlighted a regulatory gap. The Celex fire-risk monitoring cell had issued a warning on 10 August stating that fire risk in open environments was “high” until 15 August. The province of Luxembourg responded by issuing a circular banning mowing work until 14 August. However, the Hautes Fagnes area—located in Liege province, just 20 kilometers from the Luxembourg border—was not subject to this explicit prohibition.

Herve Jamar, Governor of Liege Province, defended his preventive measures, which included a police order published on 2 July and valid until 6 September. “We took a clear and firm order regarding risks and fires for the entire province of Liege,” he said. “I don’t see what more I could have done. Look, I’m not going to forbid a harvester from operating.”

Scientists Had Warned of the Risk

The fire’s location was no surprise to researchers. In 2025, a map published by the Agence wallonne de l’Air et du Climat (AWAC), produced by researchers at the University of Liege, had identified the Hautes Fagnes as one of three high-risk zones for wildfires in Wallonia. As RTBF reported, the burned area corresponds almost exactly to the zone marked in bright red on that map.

“When I compared the map I had produced last year with the current fire, the finding was quite striking,” said Julian Jacquemin, a geographer-urbanist and researcher at ULiège. “We see that the vulnerable zones we had identified are burning today.”

Climatologist Xavier Fettweis of ULiège was more blunt. “We’ve been announcing this for several years,” he said. “We had mapped several risk zones and the Hautes Fagnes were among them. Here, we should have raised the red flag on the Hautes Fagnes and on the other forests. 99% of fires are unintentionally caused by humans. If there’s no human, there’s no fire.”

The Broader Questions

The fire has raised significant questions about Belgium’s preparedness for increasingly frequent wildfires driven by climate change. At its peak, the blaze required the mobilization of Belgian fire services, the DNF, civil protection, federal police helicopters, and international reinforcements through the EU Civil Protection Mechanism, including Norwegian helicopters and French forest fire experts.

French forestry technician David Roussel, who arrived via the EU mechanism to help investigate the fire’s causes, noted that conditions on 14 August were particularly favorable for accidental fire outbreaks. “We have ambient drought, vegetation drought, litter drought, soil drought, temperature, wind, humidity—which is a very important factor,” he explained. “On that day of 14 August, we had a number of indicators showing that the situation was favorable for accidental fire outbreaks.”

Two experts—one specializing in fire and one in vehicle mechanics—have been mandated by the prosecutor. Their definitive reports are expected to take several months. The municipality of Baelen has announced it will file a civil suit against X in connection with the fire.

What to Watch For

As the investigation continues, several questions remain unanswered: whether the mowing machine’s activity can be definitively linked to the fire’s origin, whether regulatory gaps in mowing restrictions will be addressed, and how Belgium will adapt its wildfire prevention and response capabilities for a warming climate. The answers will shape not only the legal outcome of this case but also how the country prepares for what scientists warn will be increasingly frequent wildfire seasons in the years ahead.