Son La fire, March 2026 Son La, Thuan Chau, Muong La
The fire started on 18 March 2026 in Son La, Vietnam, and satellites saw it burning for 4 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 3,829 hectares from heat detections, spread across 3 municipalities.
It is the 2th largest in Sơn La since 2016 (of 58 with a page). Number 12 in Vietnam in 2026, of 97.
The power measured by the satellite is low (15.1 MW in the strongest hotspot), more typical of grass or stubble burning, or a slow surface fire, than of a large crown fire.
- Burnt area
- 3,829ha
- GWIS perimeter (Copernicus)
- Duration
- 4days
- 18 Mar 2026 – 21 Mar 2026
- Municipalities hit
- 3
- districts
- Started on
- 18 Mar
- 2026
- Heat detections
- 73
- in a single hotspot: 15 MW
- Danger at start
- 10
- Low · FWI index
- Energy released
- 395MW
- sum of detected power
Where it burned
How it evolved, day by day
Fire radiative power detected each day, in megawatts, and number of hotspots. The magenta bar marks the peak day.
The weather it burned in
It had gone 0 days without rain (1 mm or more) when it started. Rain came after the fire: 1.5 mm on 22 Mar.
This area had burned before
75% of the perimeter overlaps earlier fires recorded since 2016: 997 ha in 2016, 1,142 ha in 2017, 1,074 ha in 2019, 1,127 ha in 2020, 2,352 ha in 2025. Part of it burned more than once, so the yearly figures add up to more than the 2,867 ha that had burned before.
- 1,396 ha Son La fire, March 2025 1,768 ha in total; the hectares shown are those it shares with this fire
- 1,142 ha Son La fire, March 2017 2,615 ha in total; the hectares shown are those it shares with this fire
- 1,127 ha Son La fire, February 2020 1,364 ha in total; the hectares shown are those it shares with this fire
- 1,074 ha Son La fire, March 2019 1,356 ha in total; the hectares shown are those it shares with this fire
- 997 ha Son La fire, March 2016 1,528 ha in total; the hectares shown are those it shares with this fire
- 956 ha Son La fire, March 2025 1,559 ha in total; the hectares shown are those it shares with this fire
What happened to each town
-
Son La where it started2,795 ha reached on 18 Mar8.7 %
-
538 ha reached on 18 Mar0.4 %
-
515 ha reached on 18 Mar0.4 %
Burnt area inside each municipality, from crossing the GWIS perimeter with administrative boundaries. The distance is from the town centre to the nearest fire: staying a kilometre away does not mean it reached the houses.
The weather day by day
ECMWF ERA5 reanalysis at the fire location, the standard reference for past weather, and the Canadian Fire Weather Index (the same system Copernicus uses), computed by WorldFires from that data. Days after the fire run until the first rain.
Open-Meteo.com (CC BY 4.0) · Copernicus Climate Change Service (ERA5)
| Day | High | Min. humidity | Peak gust | Rain | Danger (FWI) |
|---|---|---|---|---|---|
| 18 Mar | 28.9 °C | 48 % | 37 km/h | 0.5 mm | Low 10 |
| 19 Mar | 29.6 °C | 43 % | 39 km/h | 0.1 mm | Moderate 14 |
| 20 Mar | 30.4 °C | 40 % | 35 km/h | 0.2 mm | Moderate 15 |
| 21 Mar | 29.4 °C | 55 % | 36 km/h | 0.3 mm | Moderate 14 |
| 22 Mar after | 28.1 °C | 63 % | 37 km/h | 1.5 mm | Very low 4 |
Before and after, from space
Drag the line to compare the same ground before the fire and after it.
If the day is cloudy, change the date: each satellite passes once a day. In false colour the burnt ground looks brown or red.
The smoke
CAMS · CopernicusOn 20 March 2026 the air beside the fire reached 52 µg/m³ of PM2.5. That day averaged 41: 2.7 times the WHO daily guideline (15).
Particles from the Copernicus CAMS model at the centre of the perimeter; these are not measurements in each town. The pale bar is the worst hour, the solid one the daily average.
Open-Meteo.com (CC BY 4.0) · Copernicus Atmosphere Monitoring Service (CAMS)
Detections table · 73Every satellite heat detection, one by one, with time, satellite, power and coordinates.
| Date and time | Satellite | FRP (MW) | Lat | Lon |
|---|
Other fires nearby
Frequently asked questions
- How long did the Son La fire last?
- GWIS (Copernicus) dates it between 18 March 2026 and 21 March 2026: 4 days between the first and last heat detection of the perimeter.
- How much area did it burn?
- The perimeter GWIS (Copernicus) rebuilt from heat detections is 3,829 hectares (38.3 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire entered 3 municipalities: Son La (2,795 ha, 8.7 %); Thuan Chau (538 ha, 0.4 %); Muong La (515 ha, 0.4 %).
- What was the weather like?
- During the fire the temperature reached 30.4 °C, humidity dropped to 40 % and gusts hit 39 km/h. The fire danger index (FWI) reached 15, class Moderate.
- Where does this data come from?
- From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Vietnam (geoBoundaries). It is not an official report.
Where to verify it
A satellite detection is not an official report. Final figures and the fire’s status are published by each country’s emergency service.
Emergency number: 114
Satellite cross-check
Does something look wrong on this page?
This page is built from satellite data and official records, and it sometimes gets things wrong: the wrong dates, the wrong town, two fires merged into one, or something that was not a wildfire at all. If you know this fire first-hand (you live nearby, saw it, fought it or reported on it), tell us what really happened and we will check it.
Report an error
Where this data comes from
The perimeter comes from the Copernicus Global Wildfire Information System (GWIS), which rebuilds it from MODIS and VIIRS heat detections and publishes it under CC BY 4.0. It is not measured on imagery as in Europe, so it is an estimate. Heat detections come from the VIIRS sensors aboard Suomi-NPP and NOAA-20, distributed by NASA FIRMS at 375 m resolution. Municipal boundaries come from geoBoundaries ADM2 (Creative Commons Attribution 3.0 Intergovernmental Organisations (CC BY 3.0 IGO)). The area per municipality is computed by WorldFires by crossing the perimeter with those boundaries, so it may differ from each country’s official figure.