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Sop Moei fire, 20 March 2019 สบเมย · Sop Moei, Tha Song Yang, Omkoi

Out · last detection 22 Apr 2019, 18:48 UTC

The fire started on 20 March 2019 in Sop Moei, Thailand, and satellites saw it burning for 34 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 12,437 hectares from heat detections, spread across 3 municipalities.

It is the 7th largest in Mae Hong Son Province since 2016 (of 361 with a page). Number 6 in Thailand in 2019, of 385.

Compare with…

Suggestions: Mae Sariang · 2020Hpa-An · 2017Sop Moei · 2016Omkoi · 2017

Burnt area
12,437ha
GWIS perimeter (Copernicus)
Duration
34days
20 Mar 2019 – 22 Apr 2019
Municipalities hit
3
districts
Started on
20 Mar
2019
Heat detections
577
in a single hotspot: 53 MW
Danger at start
33
High · FWI index
Average daily power
65MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 20 Mar22 Apr
22 Apr 2019

How it evolved, day by day

20 Mar 2019 · 4 MW · 1 23 Mar 2019 · 3 MW · 2 24 Mar 2019 · 70 MW · 14 25 Mar 2019 · 211 MW · 59 26 Mar 2019 · 11 MW · 4 28 Mar 2019 · 18 MW · 12 29 Mar 2019 · 118 MW · 36 30 Mar 2019 · 120 MW · 42 31 Mar 2019 · 114 MW · 52 1 Apr 2019 · 197 MW · 49 2 Apr 2019 · 47 MW · 17 3 Apr 2019 · 1 MW · 1 4 Apr 2019 · 12 MW · 9 5 Apr 2019 · 43 MW · 19 6 Apr 2019 · 55 MW · 15 7 Apr 2019 · 54 MW · 20 8 Apr 2019 · 12 MW · 6 9 Apr 2019 · 134 MW · 36 10 Apr 2019 · 109 MW · 35 11 Apr 2019 · 51 MW · 24 12 Apr 2019 · 11 MW · 4 13 Apr 2019 · 245 MW · 19 14 Apr 2019 · 73 MW · 12 15 Apr 2019 · 88 MW · 30 16 Apr 2019 · 67 MW · 24 17 Apr 2019 · 54 MW · 13 18 Apr 2019 · 31 MW · 4 19 Apr 2019 · 11 MW · 2 20 Apr 2019 · 16 MW · 6 21 Apr 2019 · 13 MW · 5 22 Apr 2019 · 22 MW · 5
20 Mar 30 Mar 6 Apr 13 Apr 20 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
44km/h · peak gust
23%lowest humidity

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

This area had burned before

71% of the perimeter overlaps earlier fires recorded since 2016: 5,989 ha in 2016, 3,892 ha in 2017, 3,798 ha in 2018. Part of it burned more than once, so the yearly figures add up to more than the 8,851 ha that had burned before.

How big is it?

10 km
It burned the equivalent of 7.9% of the area of London (124 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. Sop Moei สบเมย where it started
    8,479 ha reached on 20 Mar
    5.9 %
  2. Tha Song Yang ท่าสองยาง
    3,278 ha reached on 5 Apr
    1.7 %
  3. Omkoi อมก๋อย
    788 ha reached on 28 Mar
    0.3 %

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 area0.40 ha
Residents≈ 90

Inside the perimeter there were about 0.40 hectares of built-up land and about 90 residents (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)

Started with 60 days without rain: 14 % of the area in Thailand

Day High Min. humidity Peak gust Rain Danger (FWI)
20 Mar 34.5 °C 32 % 44 km/h 0.0 mm High 33
21 Mar 34.9 °C 29 % 36 km/h 0.0 mm High 33
22 Mar 34.9 °C 30 % 31 km/h 0.0 mm High 31
23 Mar 36.2 °C 28 % 31 km/h 0.0 mm High 34
24 Mar 35.9 °C 26 % 38 km/h 0.0 mm High 37
25 Mar 37.0 °C 25 % 34 km/h 0.0 mm High 37
26 Mar 36.8 °C 28 % 32 km/h 0.0 mm High 37
27 Mar 33.5 °C 45 % 37 km/h 1.5 mm Moderate 18
28 Mar 34.3 °C 33 % 38 km/h 0.0 mm High 30
29 Mar 35.4 °C 25 % 31 km/h 0.0 mm High 34
30 Mar 35.6 °C 33 % 31 km/h 0.0 mm High 36
31 Mar 35.0 °C 26 % 38 km/h 0.0 mm High 37
1 Apr 35.8 °C 23 % 40 km/h 0.0 mm Very high 39
2 Apr 36.6 °C 27 % 36 km/h 0.0 mm Very high 39
3 Apr 36.2 °C 28 % 32 km/h 0.0 mm High 37
4 Apr 35.5 °C 33 % 32 km/h 0.2 mm High 36
5 Apr 36.1 °C 30 % 34 km/h 0.1 mm High 37
6 Apr 36.2 °C 30 % 36 km/h 0.2 mm High 37
7 Apr 36.2 °C 28 % 39 km/h 0.0 mm Very high 39
8 Apr 36.0 °C 32 % 36 km/h 0.0 mm High 38
9 Apr 36.0 °C 33 % 36 km/h 0.4 mm High 37
10 Apr 36.6 °C 29 % 36 km/h 0.0 mm Very high 38
11 Apr 37.4 °C 29 % 35 km/h 0.0 mm Very high 38
12 Apr 36.6 °C 33 % 36 km/h 0.0 mm Very high 39
13 Apr 37.2 °C 30 % 39 km/h 0.0 mm Very high 40
14 Apr 37.2 °C 31 % 41 km/h 0.0 mm Very high 40
15 Apr 37.3 °C 33 % 38 km/h 0.0 mm Very high 39
16 Apr 38.3 °C 30 % 34 km/h 0.0 mm Very high 38
17 Apr 37.4 °C 34 % 35 km/h 0.3 mm High 37
18 Apr 37.7 °C 40 % 34 km/h 0.0 mm High 36
19 Apr 37.6 °C 34 % 43 km/h 0.0 mm High 38
20 Apr 37.1 °C 40 % 32 km/h 0.0 mm High 33
21 Apr 35.6 °C 43 % 35 km/h 0.0 mm High 31
22 Apr 37.8 °C 33 % 35 km/h 0.0 mm High 32
23 Apr after 37.2 °C 31 % 32 km/h 0.5 mm High 33
24 Apr after 37.3 °C 37 % 32 km/h 0.1 mm High 33
25 Apr after 36.5 °C 36 % 32 km/h 0.0 mm High 32
26 Apr after 39.1 °C 28 % 32 km/h 0.1 mm High 36
27 Apr after 38.4 °C 29 % 40 km/h 0.0 mm Very high 39
28 Apr after 37.0 °C 32 % 41 km/h 0.0 mm Very high 38
29 Apr after 37.9 °C 31 % 38 km/h 0.0 mm Very high 39
30 Apr after 37.4 °C 32 % 42 km/h 0.0 mm Very high 40
1 May after 34.8 °C 48 % 40 km/h 0.8 mm High 25
2 May after 35.0 °C 49 % 39 km/h 0.0 mm High 24

Its twins: fires that started in the same weather

It started with an FWI of 32.7, a minimum humidity of 32% and more than two months without rain. Fires in the area that started in weather like this since 2016: 36.

FWI at the start 32.7
Minimum humidity 32 %
Days without rain 60+
this fire chosen twins rest of the area
Almost identicalSimilar

Outlines of the closest twins

Mae Sariang fire, March 2020
4,050 ha 23 days FWI 32.6 Min. humidity 31 % 44 km away, in 2020

First rain (1 mm or more) after it ended: none in the following ten days.

See its page Compare with this fire

What happened to them

12 days
median duration
2,095 ha
median area
100 %
went past 1,000 ha
1.7 mm
rain at the end (median; 17 of 36 had it)

It was 5.9 times larger than the median of its twins and lasted 34 days, against 12 days.

Only 1 of its 36 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 19 of 36, 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 1.7 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

—first rain
—no rain in ten days
44km/h · max. gust

It was considered over on 22 Apr, and not even 1 mm fell in the following ten days: it went out without rain. Twins with rain when they ended: 17 of 36, with a median of 1.7 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 · 13 Mar 2019
After · 29 Apr 2019

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 · 577Every 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 Sop Moei fire last?
According to the heat detections seen by satellite inside the perimeter, it burned from 20 March 2019 to 22 April 2019 (34 days). The perimeter dates it from 23 March 2019 to 17 April 2019.
How much area did it burn?
The perimeter GWIS (Copernicus) rebuilt from heat detections is 12,437 hectares (124.4 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire entered 3 municipalities: Sop Moei (8,479 ha, 5.9 %); Tha Song Yang (3,278 ha, 1.7 %); Omkoi (788 ha, 0.3 %).
What was the weather like?
During the fire the temperature reached 38.3 °C, humidity dropped to 23 % and gusts hit 44 km/h. The fire danger index (FWI) reached 40, 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: 36. Their median duration was 12 days and their median area 2,095 ha; 100 % went past 1,000 ha. Only 1 of its 36 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 19 of 36, 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 1.7 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. Last day with fire: 17 April 2019 → 22 April 2019.
  2. Start date: 23 March 2019 → 20 March 2019.

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; 4 polygons grouped in this page.
  • Dates adjusted with the VIIRS detections inside the perimeter, which said 23 March 2019 to 17 April 2019. 577 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.