How long did the Phan fire last?

GWIS (Copernicus) dates it between 2 April 2023 and 7 April 2023: 6 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 1,091 hectares (10.9 km²). It is an estimate: official national figures may differ.

Which municipalities burned?

The fire entered 2 municipalities: Phan (998 ha, 1.0 %); Mae Chai (98 ha, 0.3 %).

What was the weather like?

During the fire the temperature reached 37.4 °C, humidity dropped to 21 % and gusts hit 36 km/h. The fire danger index (FWI) reached 37, class High.

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.

TH · Thailand · 2023-04-02 → 2023-04-07

Phan fire, April 2023 Phan, Mae Chai

Out · last detection 7 Apr 2023, 18:37 UTC

The fire started on 2 April 2023 in Phan, Thailand, and satellites saw it burning for 6 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 1,091 hectares from heat detections, spread across 2 municipalities.

It is the 262th largest in Chiang Rai Province since 2016 (of 303 with a page). Number 433 in Thailand in 2023, of 500.

The power measured by the satellite is low (26.1 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: 1,091ha; GWIS perimeter (Copernicus)
Duration: 6days; 2 Apr 2023 – 7 Apr 2023
Municipalities hit: 2; districts
Started on: 2 Apr; 2023
Heat detections: 35; in a single hotspot: 26 MW
Danger at start: 28; High · FWI index
Energy released: 176MW; sum of detected power

Play back 7 Apr 2023

HOTSPOTS BY DAY 2 Apr7 Apr

How it evolved, day by day

234567

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

The weather it burned in

37°high

36km/h · peak gust

21%lowest humidity

It had gone one day without rain (1 mm or more) when it started.

This area had burned before

75% of the perimeter overlaps earlier fires recorded since 2016: 420 ha in 2016, 21 ha in 2020, 506 ha in 2021. Part of it burned more than once, so the yearly figures add up to more than the 821 ha that had burned before.

What happened to each town

Phan where it started

998 ha reached on 2 Apr

1.0 %
Mae Chai

98 ha reached on 28 Mar

0.3 %

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)
22 Mar	36.3 °C	27 %	35 km/h	0.0 mm	High 28
23 Mar	36.8 °C	26 %	32 km/h	1.1 mm	High 25
24 Mar	35.9 °C	29 %	23 km/h	0.0 mm	High 24
25 Mar	35.3 °C	30 %	20 km/h	0.0 mm	High 25
26 Mar	36.5 °C	28 %	22 km/h	0.0 mm	High 26
27 Mar	35.8 °C	33 %	23 km/h	0.0 mm	High 27
28 Mar	37.4 °C	21 %	36 km/h	0.0 mm	High 37
29 Mar	36.0 °C	27 %	28 km/h	0.0 mm	High 32
30 Mar	36.3 °C	30 %	20 km/h	0.0 mm	High 30
31 Mar	35.5 °C	34 %	22 km/h	0.0 mm	High 28
1 Apr	36.4 °C	34 %	30 km/h	0.0 mm	High 32
2 Apr	37.1 °C	27 %	36 km/h	0.0 mm	High 35
3 Apr	35.2 °C	30 %	33 km/h	0.0 mm	High 35
4 Apr	36.5 °C	27 %	21 km/h	0.0 mm	High 31
5 Apr	36.0 °C	27 %	19 km/h	0.0 mm	High 31
6 Apr	36.1 °C	32 %	19 km/h	0.0 mm	High 32
7 Apr	36.8 °C	34 %	20 km/h	0.0 mm	High 32
8 Apr after	36.5 °C	38 %	24 km/h	0.0 mm	High 31
9 Apr after	38.0 °C	33 %	33 km/h	0.0 mm	High 34
10 Apr after	38.2 °C	32 %	24 km/h	0.0 mm	High 31
11 Apr after	38.2 °C	33 %	20 km/h	0.0 mm	High 32
12 Apr after	38.2 °C	29 %	20 km/h	0.0 mm	High 32
13 Apr after	38.8 °C	34 %	21 km/h	0.0 mm	High 32
14 Apr after	39.4 °C	30 %	20 km/h	0.0 mm	High 33
15 Apr after	38.2 °C	30 %	21 km/h	0.0 mm	High 34
16 Apr after	39.4 °C	31 %	28 km/h	0.0 mm	High 35
17 Apr after	38.4 °C	34 %	27 km/h	0.0 mm	High 36

Before and after, from space

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

↔

Before · 26 Mar 2023

After · 14 Apr 2023

Before After

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 31 March 2023 the air beside the fire reached 117 µg/m³ of PM2.5. That day averaged 68: 4.6 times the WHO daily guideline (15).

PM2.5 peak117 µg/m³

Days over the guideline11 days

PM10168 µg/m³

Optical depth1.82

WHO 15

3112345678910

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 · 35Every 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 time	Satellite	FRP (MW)	Lat	Lon

Other fires nearby

All fires in Thailand ›

Frequently asked questions

How long did the Phan fire last?: GWIS (Copernicus) dates it between 2 April 2023 and 7 April 2023: 6 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 1,091 hectares (10.9 km²). It is an estimate: official national figures may differ.
Which municipalities burned?: The fire entered 2 municipalities: Phan (998 ha, 1.0 %); Mae Chai (98 ha, 0.3 %).
What was the weather like?: During the fire the temperature reached 37.4 °C, humidity dropped to 21 % and gusts hit 36 km/h. The fire danger index (FWI) reached 37, class High.
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.

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

Satellite cross-check

NASA FIRMS ↗
GWIS · Copernicus ↗

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.

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What really happened?

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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.

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.

Where it burned