Nalae fire, April 2023 Nalae, Xay
The fire started on 6 April 2023 in Nalae, Laos, and satellites saw it burning for 17 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 3,443 hectares from heat detections, spread across 2 municipalities.
It is the 6th largest in Luang Namtha since 2016 (of 36 with a page). Number 74 in Laos in 2023, of 214.
- Burnt area
- 3,443ha
- GWIS perimeter (Copernicus)
- Duration
- 17days
- 6 Apr 2023 – 22 Apr 2023
- Municipalities hit
- 2
- districts
- Started on
- 6 Apr
- 2023
- Heat detections
- 148
- in a single hotspot: 217 MW
- Danger at start
- 33
- High · FWI index
- Average daily power
- 373MW
- detected power per day, on average
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 20 days without rain (1 mm or more) when it started. Rain came after the fire: 6.2 mm on 26 Apr.
This area had burned before
42% of the perimeter overlaps earlier fires recorded since 2016: 639 ha in 2016, 607 ha in 2017, 52 ha in 2018, 75 ha in 2020, 436 ha in 2021. Part of it burned more than once, so the yearly figures add up to more than the 1,429 ha that had burned before.
- 52 ha Nalae fire, April 2018 3,231 ha in total; the hectares shown are those it shares with this fire
- 40 ha Nalae fire, March 2020 2,098 ha in total; the hectares shown are those it shares with this fire
- 27 ha Namor fire, April 2017 29,869 ha in total; the hectares shown are those it shares with this fire
What happened to each town
-
Nalae where it started2,792 ha reached on 6 Apr1.6 %
-
669 ha reached on 9 Apr0.3 %
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) |
|---|---|---|---|---|---|
| 6 Apr | 36.1 °C | 29 % | 25 km/h | 0.0 mm | High 33 |
| 7 Apr | 35.6 °C | 32 % | 37 km/h | 0.0 mm | High 36 |
| 8 Apr | 34.6 °C | 40 % | 32 km/h | 0.0 mm | High 30 |
| 9 Apr | 35.6 °C | 41 % | 40 km/h | 0.2 mm | High 31 |
| 10 Apr | 37.7 °C | 27 % | 34 km/h | 0.0 mm | High 35 |
| 11 Apr | 38.2 °C | 27 % | 29 km/h | 0.0 mm | High 34 |
| 12 Apr | 37.9 °C | 26 % | 31 km/h | 0.0 mm | High 36 |
| 13 Apr | 37.7 °C | 31 % | 33 km/h | 0.0 mm | High 38 |
| 14 Apr | 38.5 °C | 29 % | 30 km/h | 0.0 mm | High 36 |
| 15 Apr | 38.0 °C | 29 % | 25 km/h | 0.0 mm | High 35 |
| 16 Apr | 37.1 °C | 39 % | 41 km/h | 0.0 mm | High 34 |
| 17 Apr | 37.0 °C | 34 % | 37 km/h | 0.0 mm | High 36 |
| 18 Apr | 39.2 °C | 27 % | 38 km/h | 0.0 mm | Very high 40 |
| 19 Apr | 39.2 °C | 25 % | 36 km/h | 0.0 mm | Very high 40 |
| 20 Apr | 38.4 °C | 25 % | 37 km/h | 0.0 mm | Very high 42 |
| 21 Apr | 38.6 °C | 26 % | 35 km/h | 0.0 mm | Very high 40 |
| 22 Apr | 36.9 °C | 35 % | 37 km/h | 2.3 mm | Moderate 21 |
| 23 Apr after | 38.5 °C | 27 % | 34 km/h | 0.0 mm | High 33 |
| 24 Apr after | 35.4 °C | 35 % | 36 km/h | 0.0 mm | High 32 |
| 25 Apr after | 37.3 °C | 33 % | 28 km/h | 0.1 mm | High 31 |
| 26 Apr after | 33.1 °C | 51 % | 36 km/h | 6.2 mm | Low 6 |
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.
Detections table · 148Every 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 Nalae fire last?
- According to the heat detections seen by satellite inside the perimeter, it burned from 6 April 2023 to 22 April 2023 (17 days). The perimeter dates it from 6 April 2023 to 16 April 2023.
- How much area did it burn?
- The perimeter GWIS (Copernicus) rebuilt from heat detections is 3,443 hectares (34.4 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire entered 2 municipalities: Nalae (2,792 ha, 1.6 %); Xay (669 ha, 0.3 %).
- What was the weather like?
- During the fire the temperature reached 39.2 °C, humidity dropped to 25 % and gusts hit 41 km/h. The fire danger index (FWI) reached 42, class Very high.
- Where does this data come from?
- From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Laos (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.
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.