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Bo Rai fire, February 2023 บ่อไร่ · Bo Rai

Out · last detection 8 Mar 2023, 07:07 UTC

The fire started on 22 February 2023 in Bo Rai, Thailand, and satellites saw it burning for 15 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 3,766 hectares from heat detections, spread across a single municipality.

Number 33 in Thailand in 2023, of 369.

Compare with…
Burnt area
3,766ha
GWIS perimeter (Copernicus)
Duration
15days
22 Feb 2023 – 8 Mar 2023
Municipalities hit
1
districts
Started on
22 Feb
2023
Heat detections
165
in a single hotspot: 97 MW
Danger at start
12
Moderate · FWI index
Average daily power
152MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 22 Feb8 Mar
8 Mar 2023

How it evolved, day by day

28 Feb 2023 · 122 MW · 12 1 Mar 2023 · 24 MW · 6 2 Mar 2023 · 10 MW · 5 3 Mar 2023 · 82 MW · 10 4 Mar 2023 · 525 MW · 36 5 Mar 2023 · 466 MW · 62 6 Mar 2023 · 133 MW · 31 7 Mar 2023 · 5 MW · 1 8 Mar 2023 · 6 MW · 2
28 Feb 2 Mar 4 Mar 6 Mar 8 Mar

Fire radiative power detected each day, in megawatts, and number of hotspots. The magenta bar marks the peak day.

The weather it burned in

33°high
59km/h · peak gust
38%lowest humidity

It had gone 6 days without rain (1 mm or more) when it started. Rain came after the fire: 1.5 mm on 12 Mar.

This area had burned before

86% of the perimeter overlaps earlier fires recorded since 2016: 2,199 ha in 2016, 569 ha in 2019, 2,065 ha in 2020, 1,171 ha in 2021. Part of it burned more than once, so the yearly figures add up to more than the 3,255 ha that had burned before.

How big is it?

10 km
It burned the equivalent of 2.4% of the area of London (38 km² against 1,583 km²).

London boundary: geoBoundaries · Office for National Statistics (Open Government Licence v3.0).

This compares size, not location: both shapes are at the same scale, north up, centred on each other.

What happened to each town

  1. Bo Rai บ่อไร่ where it started
    2,785 ha reached on 28 Feb
    4.1 %

Burnt area inside each municipality, from crossing the GWIS perimeter with administrative boundaries. The distance runs from the point marking the centre of each area to the nearest fire: staying a kilometre away does not mean it reached the houses.

People and buildings inside the perimeter

GHSL 2025
Built-up area0.56 ha
Residents≈ 100

Inside the perimeter there were about 0.56 hectares of built-up land and about 100 residents (GHSL 2025, satellite-based estimate).

This is an estimate on 100 m cells, made from satellite imagery and census data: it does not mean that homes burned or that anyone was harmed. The perimeter also contains land that never burned. The GHSL 2025 epoch is a projection made from 2020 and earlier data.

Source: Global Human Settlement Layer (GHS-BUILT-S and GHS-POP R2023A), European Commission Joint Research Centre (JRC), © European Union, CC BY 4.0. Sum inside the perimeter computed by WorldFires. human-settlement.emergency.copernicus.eu

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)
22 Feb 31.6 °C 42 % 39 km/h 0.0 mm Moderate 12
23 Feb 31.7 °C 46 % 32 km/h 0.0 mm Low 11
24 Feb 32.9 °C 38 % 37 km/h 0.0 mm Moderate 14
25 Feb 30.1 °C 41 % 53 km/h 0.0 mm Moderate 17
26 Feb 29.3 °C 42 % 59 km/h 0.0 mm Moderate 19
27 Feb 29.9 °C 46 % 52 km/h 0.0 mm Moderate 17
28 Feb 32.2 °C 43 % 49 km/h 0.0 mm Moderate 17
1 Mar 33.2 °C 44 % 45 km/h 0.0 mm Moderate 17
2 Mar 32.9 °C 48 % 44 km/h 0.2 mm Moderate 17
3 Mar 32.3 °C 41 % 41 km/h 0.0 mm Moderate 18
4 Mar 31.5 °C 40 % 44 km/h 0.0 mm Moderate 18
5 Mar 30.9 °C 43 % 41 km/h 0.0 mm Moderate 18
6 Mar 31.8 °C 38 % 38 km/h 0.0 mm Moderate 19
7 Mar 32.5 °C 41 % 35 km/h 0.0 mm Moderate 18
8 Mar 33.2 °C 39 % 34 km/h 0.0 mm Moderate 18
9 Mar after 32.6 °C 43 % 34 km/h 0.0 mm Moderate 19
10 Mar after 32.8 °C 46 % 28 km/h 0.0 mm Moderate 18
11 Mar after 34.0 °C 44 % 22 km/h 0.1 mm Moderate 18
12 Mar after 31.2 °C 63 % 27 km/h 1.5 mm Very low 5

Its twins: fires that started in the same weather

It started with an FWI of 11.9, a minimum humidity of 42% and 6 days without rain. Fires in the area that started in weather like this since 2016: 20.

FWI at the start 11.9
Minimum humidity 42 %
Days without rain 6
this fire chosen twins rest of the area
Almost identicalSimilar

Outlines of the closest twins

Samlout fire, February 2021
3,137 ha 8 days FWI 17.5 Min. humidity 42 % 12 km away, in 2021

First rain (1 mm or more) after it ended: 1.3 mm on 28 Feb.

What happened to them

8 days
median duration
2,980 ha
median area
100 %
went past 1,000 ha
2.6 mm
rain at the end (median; 15 of 20 had it)

It burned an area similar to its twins (3,766 ha against a median of 2,980 ha) and lasted 15 days, against 8 days.

In 5 of 20, not even 1 mm fell in the ten days after the end: they went out without rain. In the rest, the first rainy day brought a median of 2.6 mm.

This is a bank of analogues: it shows what usually happens, not what will happen. With fewer than 15 twins we give no figures. How we calculate it

How it ended

1.5 mmfirst rain
12 Mar4 days after it ended
59km/h · max. gust

It was considered over on 8 Mar, and on 12 Mar 1.5 mm fell. We do not know whether the rain or the firefighters put it out. Twins with rain when they ended: 15 of 20, with a median of 2.6 mm.

Weather on this page: Open-Meteo.com (CC BY 4.0) · Copernicus Climate Change Service (ERA5)

How a twin is chosen

  • Same area: fires that have already ended, less than 250 km from this one, since 2016.
  • Same start: we compare the FWI on the first day, the minimum humidity that day and the run of days without rain before it. The slider sets how much they may differ.
  • Only pages with final weather data (ERA5 reanalysis) calculated in the same way as this fire’s; agricultural and grass burns and pages with data under review are left out.
  • Fires burning at the same time as this one (a week before or after) are left out: they share the same spell of weather and do not count as a precedent.
  • They are sorted by similarity, and the outlines of the first five are drawn.

How we calculate it

Before and after, from space

Drag the line to compare the same ground before the fire and after it.

Before · 15 Feb 2023
After · 15 Mar 2023

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 · Copernicus

On 8 March 2023 the air beside the fire reached 101 µg/m³ of PM2.5. That day averaged 54: 3.6 times the WHO daily guideline (15).

PM2.5 peak101 µg/m³
Days over the guideline16 days
PM10145 µg/m³
Optical depth1.10
20 Feb24 Feb28 Feb4 Mar8 Mar
Good Fair Moderate Poor Very poor Extremely poor

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 · 165Every satellite heat detection, one by one, with time, satellite, power and coordinates.
⬇ Download CSV Times in UTC. Each detection is a 375 m pixel: a large fire yields hundreds per pass.
Date and timeSatelliteFRP (MW)LatLon

Other fires nearby

All fires in Thailand

Frequently asked questions

How long did the Bo Rai fire last?
GWIS (Copernicus) dates it between 22 February 2023 and 8 March 2023: 15 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 3,766 hectares (37.7 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire only entered Bo Rai (2,785 ha, 4.1 %).
What was the weather like?
During the fire the temperature reached 33.2 °C, humidity dropped to 38 % and gusts hit 59 km/h. The fire danger index (FWI) reached 19, class Moderate.
Where does this data come from?
From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Thailand (geoBoundaries). It is not an official report.
How did the fires that started in similar weather in this area end?
Fires less than 250 km away that started since 2016 with a similar FWI, humidity and dry spell: 20. Their median duration was 8 days and their median area 2,980 ha; 100 % went past 1,000 ha. In 5 of 20, not even 1 mm fell in the ten days after the end: they went out without rain. In the rest, the first rainy day brought a median of 2.6 mm.

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: 199 · 191 · Emergency number and official warnings

Satellite cross-check

History of this page Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.

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
What do you think is wrong?

We will only use your email to reply about this report. Privacy. This is not an emergency service: if there is a fire now, call 199 · 191.

How we know this
  • Perimeter: GWIS (Copernicus), rebuilt from heat detections rather than mapped on imagery.
  • Dates from the perimeter: the VIIRS detections inside it did not change them. 165 Suomi-NPP VIIRS detections on those dates.
  • We have not matched this page with any official record.
  • Weather: Copernicus ERA5 reanalysis at the fire location, in cells of about 25 km.
  • Built-up area and population come from the JRC Global Human Settlement Layer (epoch 2025, 100 m cells), summed inside the perimeter: an estimate of what was there, not a damage count.

How we build fire pages: methodology

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.