High Fens Wildfire / Belgium: Technical Analysis, Map & Fire Behaviour

The fire in 10 seconds

Current situation: about 3,000 hectares, under control throughout — but residual fire remains active

The fire began on 14 August at approximately 13:06 in the municipality of Baelen, near Jalhay. The acting Governor of Liège activated the provincial emergency phase during the afternoon. At 16:00 the affected area was estimated at about 60 hectares; by 20:00 authorities were reporting around 100 hectares and rapid, wind-sensitive propagation.

The escalation on 15 August was exceptional: almost 850 hectares were reported at 07:00, Reuters cited about 1,600 hectares during the afternoon, and the provincial estimate reached approximately 2,700 hectares at 18:00. The latest consolidated official area located by Tecnobosque remains about 3,000 hectares, published at 21:00 on 16 August. No newer validated hectare total was located by this review closure.

A major operational threshold was crossed on 20 August. At 14:00 the Governor reported the fire under control overall, with the western sector considered mastered while operations continued in the east. Around 350 people were directly involved and seven aircraft were operating, mainly over the eastern sector, where ground temperatures remained extremely high. By 18:00, the Governor reported that the fire was under control throughout the High Fens, presented no current risk of extension and was progressing toward definitive mastery.

That declaration did not mean extinguishment. During the night of 20–21 August, around 100 responders — firefighters from Wallonia and Flanders, Civil Protection, Defence and police — remained mobilised. Light drizzle before midnight temporarily increased humidity and calmed hotspots, but after midnight teams had to intervene repeatedly and continuously on several flare-ups in the north and east. A thermal-imaging drone was used to identify hotspots and guide crews on the ground.

Residual activity continued through the weekend. The Governor’s 22 August 19:00 update described the north sector as highly active and the east as active to a lesser extent. Ground operations were carried out by firefighters from the VHP, WAL and German-speaking Community rescue zones together with Defence Panther vehicles, Civil Protection support and three helicopters — two Norwegian and one Belgian Federal Police aircraft. Overnight surveillance and extinction then continued with Federal Police and Civil Protection drones.

The latest bulletin located, issued at 06:30 on 23 August, confirms that several localised flare-ups again required intervention overnight. Wind fell almost to zero, causing smoke to accumulate and become perceptible at different points around the perimeter under weak, shifting air flow. Authorities expect that smoke to disperse progressively after sunrise as temperature and mixing increase.

The residual-fire problem is therefore now the central technical issue. Earlier official reporting confirmed that burning peat soil was releasing gases including carbon monoxide; two firefighters treated for CO poisoning were reported stable. The mapped extent and depth of peat combustion remain unquantified. The Governor’s latest warning also stresses that hotspots may continue smouldering underground and can re-ignite under wind or changing weather.

Civil-protection pressure on residents has eased, but access restrictions remain severe. The evacuation measures identified in the official record were lifted by 19 August, yet public circulation remains formally prohibited across the affected forest and nature-reserve perimeter covering the Verviers, Malmedy and Elsenborn forest districts. The N68, N672 and N676 remain closed. Authorities explicitly warn that no visible flame or smoke does not mean the area is safe.

The hazards now include weakened trees and branches, buried smouldering fire, potentially harmful local smoke including possible CO, old war munitions exposed by the fire and severely affected wildlife. The Eupen and La Gileppe dam sites have reopened, but this does not authorise access to closed forest and natural areas.

Resource levels are being progressively reduced as the incident changes phase. At 18:00 on 20 August the Governor said substantial ground resources, Civil Protection and Defence “Panther” vehicles remained engaged, while lighter aircraft would continue surveillance and rapid-response work. Overnight staffing then fell to around 100 on 20–21 August. By 22 August the response had shifted again toward sector-specific ground work, supported by Defence Panthers, Civil Protection and three helicopters, followed by overnight drone-supported surveillance and extinction.

The favourable evolution has also allowed investigators to begin work on determining the ignition origin. No conclusion on cause has yet been announced.

The operational interpretation is now clear: this is no longer primarily a perimeter-expansion emergency. It is a deep-extinction, hotspot-surveillance, access-safety and ecological-damage operation that may continue after the visible fire has disappeared.

Two graphics that show why the incident changed scale

Operational reading at review time

Spatial context: border-scale smoke and support, not a reconstructed perimeter

The following graphic is an orientation map, not an incident perimeter. It places the reported start area, evacuation areas, reservoirs used for suppression logistics and the German border context in one frame. The map retains the cross-border smoke and support context from the active phase; no polygon is drawn from press reports, smoke imagery or thermal detections.

The High Fens difference: three fuel layers, three different clocks

The High Fens are not a uniform peat carpet, and the current 3,000-ha affected area must not be equated with 3,000 ha of peat combustion. The key update is that local peat combustion is now officially confirmed: the Governor reported burning peat soil releasing significant gases, including carbon monoxide. A 2024 field and UAV study in the Belgian Hautes Fagnes found strong spatial variability in peat thickness and carbon storage. That heterogeneity is why the confirmed presence of burning peat still does not quantify how much peat has burned, how deeply it has burned or how much carbon has been lost.

Technical fact sheet

Selective chronology: how a 60-ha incident became a national emergency

Behaviour chain: why the fire can change character quickly

Next 72 hours: a dry Sunday and Monday favour surface consolidation, but residual peat heat remains the key uncertainty

The Royal Meteorological Institute’s 23 August 06:00 forecast shows a more stable phase. Sunday should be generally dry, with a maximum around 16°C in the High Ardennes and a weak northerly wind becoming locally moderate. Monday remains stable, sunny and dry under an easterly wind, while Tuesday brings increasing cloud and the possibility of showers or thunderstorms. This is favourable for access, surveillance and surface drying, but it does not prove deep extinction: the 23 August official bulletin still reports localised overnight flare-ups.

Operational priorities Tecnobosque would monitor

• North / east re-ignitions: track whether the localised 22–23 August overnight flare-ups decline during Sunday daylight operations, especially after the highly active north sector reported on Saturday.
• Thermal-drone hotspot map: convert repeated thermal detections into a structured residual-heat inventory by sector and time.
• Peat / carbon monoxide: maintain deep-organic combustion and gas exposure as core responder-safety variables until cold-trailing and monitoring support stand-down.
• Weather transition: Sunday and Monday are expected to be mostly dry and stable; this helps surface operations but can also dry fine fuels around residual heat, while Tuesday may reintroduce showers and thunderstorm-driven wind shifts.
• Access safety: treat N68 / N672 / N676 closures and the forest-access ban as a separate safety layer from the fire-control status.
• Ground stability / damaged trees: monitor falling-tree and branch risk, mud, visibility and difficult access as continuing operational constraints.
• Old munitions: keep World War II munition hazards integrated into hotspot treatment and post-fire access planning.
• Ecological severity: separate surface area affected from actual peat depth consumed, habitat loss and carbon release.

Three plausible evolution scenarios

These are analytical scenarios, not deterministic forecasts. Tecnobosque does not assign probabilities without a validated incident perimeter, sector-level hotspot mapping, fuel data and operational weather observations.

What this wildfire teaches Europe

Confirmed facts vs Tecnobosque interpretation

Methodological limits