How long did the Pai fire last?

GWIS (Copernicus) dates it between 28 March 2019 and 3 April 2019: 7 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 1,629 hectares (16.3 km²). It is an estimate: official national figures may differ.

Which municipalities burned?

The fire entered 2 municipalities: Pai (1,601 ha, 0.7 %); Chiang Dao (37 ha, 0.0 %).

What was the weather like?

During the fire the temperature reached 35.9 °C, humidity dropped to 14 % and gusts hit 54 km/h. The fire danger index (FWI) reached 45, class Very 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 · 2019-03-28 → 2019-04-03

Pai fire, 28 March 2019 Pai, Chiang Dao

Out · last detection 3 Apr 2019, 19:43 UTC

The fire started on 28 March 2019 in Pai, Thailand, and satellites saw it burning for 7 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 1,629 hectares from heat detections, spread across 2 municipalities.

It is the 344th largest in Mae Hong Son Province since 2016 (of 668 with a page). Number 216 in Thailand in 2019, of 503.

Burnt area: 1,629ha; GWIS perimeter (Copernicus)
Duration: 7days; 28 Mar 2019 – 3 Apr 2019
Municipalities hit: 2; districts
Started on: 28 Mar; 2019
Heat detections: 44; in a single hotspot: 67 MW
Danger at start: 40; Very high · FWI index
Energy released: 171MW; sum of detected power

Play back 3 Apr 2019

HOTSPOTS BY DAY 28 Mar3 Apr

How it evolved, day by day

28293031123

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

The weather it burned in

36°high

54km/h · peak gust

14%lowest humidity

It had gone more than two months without rain (1 mm or more) when it started.

This area had burned before

15% of the perimeter overlaps earlier fires recorded since 2016: 185 ha in 2016, 55 ha in 2018.

What happened to each town

Pai where it started

1,601 ha reached on 24 Mar

0.7 %
Chiang Dao

37 ha

0.0 %

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)
17 Mar	34.8 °C	18 %	36 km/h	0.0 mm	Very high 40
18 Mar	35.0 °C	18 %	42 km/h	0.0 mm	Very high 42
19 Mar	33.1 °C	24 %	54 km/h	0.0 mm	Very high 45
20 Mar	33.3 °C	23 %	50 km/h	0.0 mm	Very high 44
21 Mar	33.9 °C	21 %	40 km/h	0.0 mm	Very high 42
22 Mar	34.0 °C	21 %	31 km/h	0.0 mm	Very high 38
23 Mar	34.9 °C	20 %	24 km/h	0.0 mm	High 37
24 Mar	35.4 °C	19 %	36 km/h	0.0 mm	Very high 41
25 Mar	35.9 °C	21 %	29 km/h	0.0 mm	Very high 39
26 Mar	35.5 °C	20 %	30 km/h	0.0 mm	Very high 39
27 Mar	34.0 °C	27 %	45 km/h	0.0 mm	Very high 42
28 Mar	33.2 °C	24 %	47 km/h	0.0 mm	Very high 45
29 Mar	35.4 °C	14 %	32 km/h	0.0 mm	Very high 42
30 Mar	34.7 °C	22 %	30 km/h	0.0 mm	Very high 42
31 Mar	35.1 °C	21 %	35 km/h	0.0 mm	Very high 43
1 Apr	35.6 °C	18 %	34 km/h	0.0 mm	Very high 44
2 Apr	35.7 °C	18 %	35 km/h	0.0 mm	Very high 44
3 Apr	34.6 °C	25 %	37 km/h	0.2 mm	Very high 41
4 Apr after	35.6 °C	20 %	38 km/h	0.0 mm	Very high 43
5 Apr after	35.3 °C	21 %	35 km/h	0.0 mm	Very high 42
6 Apr after	35.8 °C	21 %	33 km/h	0.0 mm	Very high 42
7 Apr after	35.9 °C	22 %	41 km/h	0.0 mm	Very high 45
8 Apr after	35.4 °C	22 %	46 km/h	0.2 mm	Very high 45
9 Apr after	35.8 °C	22 %	42 km/h	0.0 mm	Very high 45
10 Apr after	36.0 °C	19 %	45 km/h	0.0 mm	Very high 46
11 Apr after	36.8 °C	20 %	41 km/h	0.0 mm	Very high 46
12 Apr after	36.4 °C	21 %	38 km/h	0.0 mm	Very high 44
13 Apr after	36.6 °C	23 %	32 km/h	0.0 mm	Very high 43

Before and after, from space

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

↔

Before · 21 Mar 2019

After · 10 Apr 2019

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.

Detections table · 44Every 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 Pai fire last?: GWIS (Copernicus) dates it between 28 March 2019 and 3 April 2019: 7 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 1,629 hectares (16.3 km²). It is an estimate: official national figures may differ.
Which municipalities burned?: The fire entered 2 municipalities: Pai (1,601 ha, 0.7 %); Chiang Dao (37 ha, 0.0 %).
What was the weather like?: During the fire the temperature reached 35.9 °C, humidity dropped to 14 % and gusts hit 54 km/h. The fire danger index (FWI) reached 45, class Very 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 do you think is wrong?

Dates or duration Place or towns Burned area Name It was not a wildfire Same fire as another page Something else

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