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TH · Thailand · –

Umphang fire, 21 March 2020 อุ้มผาง · Umphang

Out · last detection 13 Apr 2020, 18:54 UTC

The fire started on 21 March 2020 in Umphang, Thailand, and satellites saw it burning for 24 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 2,536 hectares from heat detections, spread across a single municipality.

It is the 58th largest in Tak Province since 2016 (of 266 with a page). Number 107 in Thailand in 2020, of 457.

The power measured by the satellite is low (15.4 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
2,536ha
GWIS perimeter (Copernicus)
Duration
24days
21 Mar 2020 – 13 Apr 2020
Municipalities hit
1
districts
Started on
21 Mar
2020
Heat detections
112
in a single hotspot: 15 MW
Danger at start
37
High · FWI index
Average daily power
20MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 21 Mar13 Apr
13 Apr 2020

How it evolved, day by day

21 Mar 2020 · 1 MW · 1 22 Mar 2020 · 4 MW · 1 26 Mar 2020 · 92 MW · 12 27 Mar 2020 · 14 MW · 3 28 Mar 2020 · 23 MW · 6 29 Mar 2020 · 7 MW · 2 30 Mar 2020 · 15 MW · 4 31 Mar 2020 · 13 MW · 3 1 Apr 2020 · 9 MW · 3 2 Apr 2020 · 9 MW · 9 3 Apr 2020 · 20 MW · 7 4 Apr 2020 · 29 MW · 2 6 Apr 2020 · 6 MW · 1 7 Apr 2020 · 8 MW · 8 8 Apr 2020 · 53 MW · 15 9 Apr 2020 · 40 MW · 9 10 Apr 2020 · 11 MW · 5 11 Apr 2020 · 20 MW · 4 12 Apr 2020 · 5 MW · 4 13 Apr 2020 · 19 MW · 13
26 Mar 1 Apr 6 Apr 10 Apr

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

The weather it burned in

38°high
49km/h · peak gust
21%lowest humidity

It had gone 4 days without rain (1 mm or more) when it started. Rain came after the fire: 1.5 mm on 14 Apr.

This area had burned before

11% of the perimeter overlaps earlier fires recorded since 2016: 52 ha in 2016, 276 ha in 2018. Part of it burned more than once, so the yearly figures add up to more than the 284 ha that had burned before.

How big is it?

10 km
It burned the equivalent of 1.6% of the area of London (25 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. Umphang อุ้มผาง where it started
    2,654 ha reached on 21 Mar
    0.6 %

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 2020
Built-up area< 0.1 ha
Residents< 20

Inside the perimeter there was no noticeable built-up land and almost nobody lived there (GHSL 2020, 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.

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)
21 Mar 34.8 °C 31 % 44 km/h 0.0 mm High 37
22 Mar 34.6 °C 31 % 46 km/h 0.0 mm High 36
23 Mar 36.3 °C 25 % 38 km/h 0.0 mm High 36
24 Mar 35.4 °C 31 % 39 km/h 0.2 mm High 37
25 Mar 34.6 °C 35 % 38 km/h 0.0 mm Very high 41
26 Mar 35.3 °C 34 % 39 km/h 0.0 mm Very high 41
27 Mar 35.5 °C 30 % 37 km/h 0.0 mm Very high 42
28 Mar 36.1 °C 23 % 38 km/h 0.0 mm Very high 46
29 Mar 36.2 °C 27 % 38 km/h 0.0 mm Very high 45
30 Mar 35.8 °C 27 % 38 km/h 0.0 mm Very high 46
31 Mar 36.9 °C 28 % 37 km/h 0.0 mm Very high 42
1 Apr 36.8 °C 31 % 46 km/h 0.0 mm Very high 45
2 Apr 37.3 °C 29 % 40 km/h 0.1 mm Very high 46
3 Apr 36.9 °C 30 % 39 km/h 0.0 mm Very high 42
4 Apr 37.5 °C 29 % 28 km/h 0.0 mm Very high 43
5 Apr 36.8 °C 32 % 34 km/h 0.0 mm High 38
6 Apr 35.7 °C 33 % 42 km/h 0.0 mm Very high 46
7 Apr 35.9 °C 31 % 41 km/h 0.0 mm Very high 46
8 Apr 35.9 °C 31 % 49 km/h 0.0 mm Very high 44
9 Apr 38.2 °C 21 % 42 km/h 0.0 mm Very high 42
10 Apr 37.7 °C 24 % 47 km/h 0.0 mm Very high 43
11 Apr 37.7 °C 23 % 39 km/h 0.0 mm Very high 42
12 Apr 37.6 °C 28 % 37 km/h 0.0 mm Very high 42
13 Apr 36.9 °C 26 % 28 km/h 1.1 mm Very high 40
14 Apr after 34.2 °C 42 % 28 km/h 1.5 mm High 22

Its twins: fires that started in the same weather

It started with an FWI of 37.2, a minimum humidity of 31% and 4 days without rain. Fires in the area that started in weather like this since 2016: 15.

FWI at the start 37.2
Minimum humidity 31 %
Days without rain 4
this fire chosen twins rest of the area
Almost identicalSimilar

Outlines of the closest twins

Sangkhla Buri fire, March 2024
1,765 ha 9 days FWI 33.5 Min. humidity 31 % 25 km away, in 2024

First rain (1 mm or more) after it ended: 13.0 mm on 19 Mar.

What happened to them

9 days
median duration
1,306 ha
median area
100 %
went past 1,000 ha
5.0 mm
rain at the end (median; 12 of 15 had it)

It was 1.9 times larger than the median of its twins and lasted 24 days, against 9 days.

Only 1 of its 15 twins burned more. The weather on the first day does not explain everything: the wind in the following days, the fuel and the firefighting also count. In 3 of 15, 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 5.0 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
14 Aprthe day after it ended
49km/h · max. gust

It was considered over on 13 Apr, and on 14 Apr 1.5 mm fell. We do not know whether the rain or the firefighters put it out. Twins with rain when they ended: 12 of 15, with a median of 5.0 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 · 14 Mar 2020
After · 20 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 · 112Every 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 Umphang fire last?
According to the heat detections seen by satellite inside the perimeter, it burned from 21 March 2020 to 13 April 2020 (24 days). The perimeter dates it from 25 March 2020 to 13 April 2020.
How much area did it burn?
The perimeter GWIS (Copernicus) rebuilt from heat detections is 2,536 hectares (25.4 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire only entered Umphang (2,654 ha, 0.6 %).
What was the weather like?
During the fire the temperature reached 38.2 °C, humidity dropped to 21 % and gusts hit 49 km/h. The fire danger index (FWI) reached 46, 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.
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: 15. Their median duration was 9 days and their median area 1,306 ha; 100 % went past 1,000 ha. Only 1 of its 15 twins burned more. The weather on the first day does not explain everything: the wind in the following days, the fuel and the firefighting also count. In 3 of 15, 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 5.0 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 · 2 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.
  1. Area: 2,640 → 2,536 ha.
  2. Start date: 25 March 2020 → 21 March 2020.

RSS Changes to this page With cross-checks and a citable version

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; 2 polygons grouped in this page.
  • Dates adjusted with the VIIRS detections inside the perimeter, which said 25 March 2020 to 13 April 2020. 112 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 2020, 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.