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Pai fire, 1 April 2020 Pai

Out · last detection 7 Apr 2020, 19:06 UTC

The fire started on 1 April 2020 in Pai, Thailand, and satellites saw it burning for 7 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 4,783 hectares from heat detections, spread across a single municipality.

It is the 67th largest in Mae Hong Son Province since 2016 (of 668 with a page). Number 53 in Thailand in 2020, of 666.

The power measured by the satellite is low (26.2 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
4,783ha
GWIS perimeter (Copernicus)
Duration
7days
1 Apr 2020 – 7 Apr 2020
Municipalities hit
1
districts
Started on
1 Apr
2020
Heat detections
185
in a single hotspot: 26 MW
Danger at start
39
Very high · FWI index
Energy released
617MW
sum of detected power

Where it burned

7 Apr 2020
HOTSPOTS BY DAY 1 Apr7 Apr

How it evolved, day by day

1234567

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
50km/h · peak gust
17%lowest humidity

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

This area had burned before

86% of the perimeter overlaps earlier fires recorded since 2016: 2,503 ha in 2016, 1,793 ha in 2017, 4,235 ha in 2019. Part of it burned more than once, so the yearly figures add up to more than the 4,109 ha that had burned before.

What happened to each town

  1. Pai where it started
    4,807 ha reached on 25 Mar
    2.1 %

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 33.3 °C 24 % 43 km/h 0.0 mm Very high 39
19 Mar 33.2 °C 23 % 32 km/h 0.0 mm High 37
20 Mar 32.9 °C 26 % 44 km/h 0.2 mm Very high 41
21 Mar 31.3 °C 30 % 49 km/h 0.4 mm Very high 39
22 Mar 31.4 °C 26 % 44 km/h 0.4 mm High 38
23 Mar 32.1 °C 23 % 46 km/h 0.0 mm Very high 39
24 Mar 32.1 °C 23 % 50 km/h 0.0 mm Very high 40
25 Mar 32.0 °C 22 % 48 km/h 0.0 mm Very high 40
26 Mar 32.4 °C 22 % 45 km/h 0.0 mm Very high 39
27 Mar 33.2 °C 25 % 36 km/h 0.0 mm High 37
28 Mar 34.5 °C 25 % 35 km/h 0.0 mm High 38
29 Mar 34.2 °C 27 % 37 km/h 0.0 mm High 38
30 Mar 34.6 °C 29 % 36 km/h 0.0 mm High 38
31 Mar 35.5 °C 26 % 35 km/h 0.0 mm High 37
1 Apr 35.4 °C 20 % 41 km/h 0.0 mm Very high 41
2 Apr 34.7 °C 21 % 46 km/h 0.0 mm Very high 43
3 Apr 35.4 °C 17 % 41 km/h 0.0 mm Very high 44
4 Apr 35.0 °C 21 % 38 km/h 0.0 mm Very high 43
5 Apr 34.6 °C 23 % 44 km/h 0.0 mm Very high 45
6 Apr 33.3 °C 29 % 46 km/h 0.0 mm Very high 41
7 Apr 33.5 °C 24 % 44 km/h 0.0 mm Very high 41
8 Apr after 33.7 °C 25 % 34 km/h 0.0 mm Very high 38
9 Apr after 33.7 °C 27 % 31 km/h 0.0 mm Very high 38
10 Apr after 34.1 °C 21 % 46 km/h 0.0 mm Very high 42
11 Apr after 34.2 °C 28 % 30 km/h 0.2 mm High 38
12 Apr after 34.2 °C 27 % 36 km/h 0.0 mm Very high 39
13 Apr after 35.6 °C 15 % 44 km/h 0.0 mm Very high 46
14 Apr after 33.7 °C 28 % 27 km/h 0.1 mm High 37
15 Apr after 33.7 °C 30 % 34 km/h 0.0 mm Very high 38
16 Apr after 34.5 °C 27 % 40 km/h 0.0 mm Very high 39
17 Apr after 34.1 °C 25 % 41 km/h 0.0 mm Very high 40

Before and after, from space

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

Before · 25 Mar 2020
After · 14 Apr 2020

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 · 185Every 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 Pai fire last?
GWIS (Copernicus) dates it between 1 April 2020 and 7 April 2020: 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 4,783 hectares (47.8 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire only entered Pai (4,807 ha, 2.1 %).
What was the weather like?
During the fire the temperature reached 35.5 °C, humidity dropped to 17 % and gusts hit 50 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

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.

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.