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TH · Thailand · –

Khun Yuam fire, March 2022 ขุนยวม · Khun Yuam

Out · last detection 19 Mar 2022, 18:35 UTC

The fire started on 11 March 2022 in Khun Yuam, Thailand, and satellites saw it burning for 9 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 1,172 hectares from heat detections, spread across a single municipality.

It is the 285th largest in Mae Hong Son Province since 2016 (of 361 with a page). Number 9 in Thailand in 2022, of 18.

The power measured by the satellite is low (5.1 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
1,172ha
GWIS perimeter (Copernicus)
Duration
9days
11 Mar 2022 – 19 Mar 2022
Municipalities hit
1
districts
Started on
11 Mar
2022
Heat detections
32
in a single hotspot: 5 MW
Danger at start
15
Moderate · FWI index
Average daily power
10MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 11 Mar19 Mar
19 Mar 2022

How it evolved, day by day

11 Mar 2022 · 2 MW · 2 12 Mar 2022 · 22 MW · 11 13 Mar 2022 · 29 MW · 12 14 Mar 2022 · 4 MW · 2 17 Mar 2022 · 6 MW · 2 18 Mar 2022 · 1 MW · 1 19 Mar 2022 · 4 MW · 2
11 Mar 13 Mar 17 Mar 19 Mar

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
38km/h · peak gust
39%lowest humidity

It had gone 0 days without rain (1 mm or more) when it started. Rain came after the fire: 11.5 mm on 21 Mar.

This area had burned before

85% of the perimeter overlaps earlier fires recorded since 2016: 358 ha in 2017, 111 ha in 2018, 462 ha in 2019, 570 ha in 2020, 835 ha in 2021. Part of it burned more than once, so the yearly figures add up to more than the 994 ha that had burned before.

How big is it?

10 km
It burned the equivalent of 0.7% of the area of London (12 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. Khun Yuam ขุนยวม where it started
    1,179 ha reached on 11 Mar
    0.7 %

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 area0.32 ha
Residents≈ 40

Inside the perimeter there were about 0.32 hectares of built-up land and about 40 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)

Day High Min. humidity Peak gust Rain Danger (FWI)
11 Mar 36.4 °C 43 % 26 km/h 0.1 mm Moderate 15
12 Mar 36.6 °C 41 % 27 km/h 0.0 mm Moderate 20
13 Mar 36.7 °C 42 % 26 km/h 0.1 mm Moderate 21
14 Mar 37.0 °C 43 % 23 km/h 0.1 mm Moderate 20
15 Mar 36.7 °C 42 % 35 km/h 0.2 mm High 23
16 Mar 36.0 °C 42 % 38 km/h 2.1 mm High 27
17 Mar 34.8 °C 46 % 36 km/h 2.2 mm Moderate 16
18 Mar 34.3 °C 44 % 28 km/h 1.4 mm Low 10
19 Mar 35.5 °C 39 % 30 km/h 0.0 mm Moderate 16
20 Mar after 35.4 °C 43 % 26 km/h 0.0 mm Moderate 19
21 Mar after 34.2 °C 49 % 26 km/h 11.5 mm Moderate 20

Its twins: fires that started in the same weather

It started with an FWI of 15.3, a minimum humidity of 43% and rain the day before. Fires in the area that started in weather like this since 2016: 22.

FWI at the start 15.3
Minimum humidity 43 %
Days without rain 0
this fire chosen twins rest of the area
Almost identicalSimilar

Outlines of the closest twins

Mae Sariang fire, March 2023
3,985 ha 17 days FWI 13.3 Min. humidity 43 % 83 km away, in 2023

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

What happened to them

10 days
median duration
1,704 ha
median area
100 %
went past 1,000 ha
2.2 mm
rain at the end (median; 11 of 22 had it)

It burned an area similar to its twins (1,172 ha against a median of 1,704 ha) and lasted 9 days, against 10 days.

In 11 of 22, 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 2.2 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

11.5 mmfirst rain
21 Mar2 days after it ended
38km/h · max. gust

It was considered over on 19 Mar, and on 21 Mar 11.5 mm fell. We do not know whether the rain or the firefighters put it out. Twins with rain when they ended: 11 of 22, with a median of 2.2 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 · 4 Mar 2022
After · 26 Mar 2022

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 · 32Every 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 Khun Yuam fire last?
According to the heat detections seen by satellite inside the perimeter, it burned from 11 March 2022 to 19 March 2022 (9 days). The perimeter dates it from 11 March 2022 to 14 March 2022.
How much area did it burn?
The perimeter GWIS (Copernicus) rebuilt from heat detections is 1,172 hectares (11.7 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire only entered Khun Yuam (1,179 ha, 0.7 %).
What was the weather like?
During the fire the temperature reached 37.0 °C, humidity dropped to 39 % and gusts hit 38 km/h. The fire danger index (FWI) reached 27, 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.
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: 22. Their median duration was 10 days and their median area 1,704 ha; 100 % went past 1,000 ha. In 11 of 22, 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 2.2 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 · 1 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.
  1. Last day with fire: 14 March 2022 → 19 March 2022.

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.
  • Dates adjusted with the VIIRS detections inside the perimeter, which said 11 March 2022 to 14 March 2022. 32 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.