Burned area
satellite only7,017ha
Perimeter published by GWIS (Copernicus).
- Source
- GWIS (Copernicus)
- Date
- 29 Apr 2025 – 15 May 2025
+− cross-check
No official record is matched to this page to compare it with.
MN · Mongolia · –
Yero'o fire, April 2025 Yero'o
Out · last detection 15 May 2025, 05:55 UTC
The fire started on 29 April 2025 in Yero'o, Mongolia, and satellites saw it burning for 17 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 7,017 hectares from heat detections, spread across a single municipality.
It is the 4th largest in Selenge since 2016 (of 17 with a page). Number 3 in Mongolia in 2025, of 11.
Use this data
Compare with…
Use this data
Fire page data · version 2026-10-26matches the official recordwith caveatssatellite onlymodel
When copying, the sentence is
Tick the figures you want: they make up the lede and the CSV.
Duration by satellite
satellite only17days
29 Apr 2025 to 15 May 2025: first and last day with fire on the page.
- Source
- GWIS (Copernicus) · NASA FIRMS · VIIRS
- Date
- last detection: 15 May 2025, 05:55 UTC
+− cross-check
Satellites pass a few times a day and cloud or smoke can hide the fire: a lack of detections is not an official extinction. Each country’s emergency service declares a fire contained or out.
Start
satellite only29 Apr 2025
First day with fire seen by the satellites or the perimeter.
- Source
- GWIS (Copernicus) · NASA FIRMS · VIIRS
- Date
- 29 Apr 2025
+− cross-check
No official record is matched to this page, so the alert time and the cause are not known here.
Hotspots
satellite only582
VIIRS detections at 375 m. Most intense hotspot: 167 MW.
- Source
- NASA FIRMS · VIIRS (Suomi NPP)
- Date
- 29 Apr 2025 – 15 May 2025
+− cross-check
There is no official record to compare with. Each hotspot is a pixel detected in one satellite pass, not a separate fire.
The worst day
satellite only1,860MW
Total radiative power on 9 May 2025; hotspots that day: 170.
- Source
- NASA FIRMS · VIIRS (FRP)
- Date
- 9 May 2025
+− cross-check
Fire radiative power (FRP) measures the energy the fire gives off when the satellite passes. Added up by day, it compares intensity, not area.
Danger at the start
model14.7FWI · moderate
Fire Weather Index (Canadian system) computed by WorldFires for the day the fire started. Consecutive days without rain before: 3.
- Source
- WorldFires calculation (Canadian FWI system)
- Date
- 29 Apr 2025, local noon
- Model
- ERA5 0,25° (ECMWF · Copernicus C3S) · Open-Meteo.com
+− cross-check
This is an index computed from weather model data, not a measurement of the fire nor an official warning. Danger warnings are issued by each country’s authority. Emergency number and official warnings
Weather during the fire
model24.4°C · 23% RH
High of 24.4 °C and minimum humidity of 23% on 11 May 2025; gusts of 68 km/h on 29 April 2025.
- Source
- weather model at the fire’s grid cell
- Date
- 29 Apr 2025 – 15 May 2025
- Model
- ERA5 0,25° (ECMWF · Copernicus C3S) · Open-Meteo.com
+− cross-check
These are model values for a cell of about 25 km, not from a weather station: they may differ from what was measured on the ground.
This page’s change log has been kept since 24 October 2026: every night what it publishes is compared and the difference is logged. Anything earlier is reconstructed from each source’s date and marked as reconstructed.
Show
-
· reconstructed weatherWeather and FWI computed from the ERA5 reanalysis
-
logLast day with fire: 11 May 2025 → 15 May 2025.
-
· reconstructed GHSLPopulation and built-up area computed
What was saved on 26 October 2026
Every night a snapshot of what the page shows is saved. If anything changes, it appears in the list as a log entry.
- Area
- 7,017 ha
- Dates
- 29 Apr 2025 – 15 May 2025
- Name
- Yero'o
- Official record
- —
Versioned permanent link
https://worldfires.org/en/fire/yero-o-2025-04?v=2026-10-26A version keeps the area, dates, name and official record; the area as it was logged (changes under 2% are not logged). The map, hotspots and weather always show today’s data.
Citation
A lede of about 60 words figures only, no adjectives
CSV for this fire yero-o-2025-04.csv · daily, no individual hotspots
| fecha | focos_viirs | frp_mw | tmax_c | tmin_c | hr_min_pct | viento_max_kmh | racha_max_kmh | precip_mm | fwi | clase_fwi | dentro_del_incendio |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 2025-04-29 | 52 | 205 | 6 | -1.2 | 18 | 26 | 68 | 0.8 | 14.7 | moderado | 1 |
| 2025-04-30 | 27 | 189 | 10.5 | -3.3 | 17 | 14.4 | 41.4 | 0 | 12.8 | moderado | 1 |
| 2025-05-01 | 11 | 39 | 8.2 | 0.6 | 26 | 17.7 | 48.6 | 0.9 | 8.3 | bajo | 1 |
| 2025-05-02 | 41 | 312 | 9.2 | -3.1 | 19 | 16.2 | 45.7 | 0 | 11.6 | moderado | 1 |
| 2025-05-03 | 11 | 74 | 13.2 | -4.2 | 20 | 10.6 | 32.8 | 0 | 12 | moderado | 1 |
| 2025-05-04 | 33 | 314 | 14.9 | -1.6 | 19 | 14.4 | 40.3 | 0 | 15.3 | moderado | 1 |
| 2025-05-05 | 17 | 140 | 13.7 | -1 | 20 | 13.1 | 37.1 | 0 | 15.3 | moderado | 1 |
| 2025-05-06 | 18 | 54 | 15 | -0.7 | 19 | 8.8 | 26.6 | 0.1 | 14.3 | moderado | 1 |
| 2025-05-07 | 20 | 35 | 15 | -1.1 | 28 | 17.5 | 46.8 | 0.2 | 18.4 | moderado | 1 |
| 2025-05-08 | 73 | 643 | 14.4 | -0.8 | 10 | 10.8 | 33.8 | 0 | 18.6 | moderado | 1 |
| 2025-05-09 | 170 | 1,860 | 18.4 | -3.1 | 19 | 10.7 | 31.3 | 0 | 19.2 | moderado | 1 |
| 2025-05-10 | 100 | 1,550 | 22.6 | 5.2 | 22 | 15.2 | 41 | 0 | 22.5 | alto | 1 |
| 2025-05-11 | 8 | 12 | 24.4 | 6.5 | 23 | 13.4 | 41.8 | 0 | 22.4 | alto | 1 |
| 2025-05-12 | 0 | 0 | 15.3 | 4.5 | 59 | 20.4 | 45 | 12.3 | 0.4 | muy_bajo | 1 |
| 2025-05-13 | 0 | 0 | 9.7 | 1.7 | 34 | 15.2 | 42.8 | 0.4 | 2.2 | muy_bajo | 1 |
| 2025-05-14 | 0 | 0 | 14.7 | 0.6 | 32 | 17.2 | 45.4 | 0.8 | 4.9 | muy_bajo | 1 |
| 2025-05-15 | 1 | 3 | 11.1 | -2.3 | 26 | 12.3 | 29.9 | 0.2 | 7.9 | bajo | 1 |
| 2025-05-16 | 0 | 0 | 8.7 | 0.3 | 25 | 19.2 | 55.1 | 0.2 | 12.5 | moderado | 0 |
| 2025-05-17 | 0 | 0 | 10.2 | -2.5 | 21 | 12.7 | 37.1 | 0.6 | 11.1 | bajo | 0 |
| 2025-05-18 | 0 | 0 | 14.7 | -1.5 | 22 | 17.2 | 46.1 | 0 | 15.6 | moderado | 0 |
| 2025-05-19 | 0 | 0 | 18.4 | 2.5 | 37 | 8.9 | 22.3 | 2.5 | 2.4 | muy_bajo | 0 |
It is generated in your browser from this page’s data: one file per fire, aggregated by day and without individual hotspots.
Live widget for your story
It updates itself while the fire is still active and links to this page. Free, with the attribution shown at the bottom.
Sources for this page: GWIS (Copernicus), NASA FIRMS (VIIRS), ERA5 (ECMWF/Copernicus C3S) · Open-Meteo.com (CC BY 4.0), GHSL (JRC). Open-Meteo.com · How we build fire pages: methodology
- Burnt area
- 7,017ha
- GWIS perimeter (Copernicus)
- Duration
- 17days
- 29 Apr 2025 – 15 May 2025
- Municipalities hit
- 1
- districts
- Started on
- 29 Apr
- 2025
- Heat detections
- 582
- in a single hotspot: 167 MW
- Danger at start
- 15
- Moderate · FWI index
- Average daily power
- 388MW
- detected power per day, on average
Where it burned
HOTSPOTS BY DAY
29 Apr15 May
15 May 2025
How it evolved, day by day
29 Apr
2 May
5 May
9 May
Fire radiative power detected each day, in megawatts, and number of hotspots. The magenta bar marks the peak day.
The weather it burned in
24°high
68km/h · peak gust
10%lowest humidity
It had gone 3 days without rain (1 mm or more) when it started. Rain came after the fire: 2.5 mm on 19 May.
This area had burned before
2% of the perimeter overlaps earlier fires recorded since 2016: 35 ha in 2018, 75 ha in 2019.
How big is it?
London boundary: geoBoundaries · Office for National Statistics (Open Government Licence v3.0).
Paris boundary: geoBoundaries · Institut national de l'information géographique et forestière (IGN-F) (Etalab Open License 2.0).
Madrid boundary: geoBoundaries · Open Data ESRI, IGN Central Registry of Cartography Area (CC BY 4.0).
Berlin boundary: geoBoundaries · Federal Agency for Cartography and Geodesy (dl-de/by-2-0).
This compares size, not location: both shapes are at the same scale, north up, centred on each other.
What happened to each town
-
Yero'o where it started6,965 ha reached on 29 Apr0.8 %
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 2025Built-up area< 0.1 ha
Residents< 20
Inside the perimeter there was no noticeable built-up land and almost nobody lived there (GHSL 2025, 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. The GHSL 2025 epoch is a projection made from 2020 and earlier data.
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 Strong wind: 56 % of the area in Mongolia
| Day | High | Min. humidity | Peak gust | Rain | Danger (FWI) |
|---|---|---|---|---|---|
| 29 Apr | 6.0 °C | 18 % | 68 km/h | 0.8 mm | Moderate 15 |
| 30 Apr | 10.5 °C | 17 % | 41 km/h | 0.0 mm | Moderate 13 |
| 1 May | 8.2 °C | 26 % | 49 km/h | 0.9 mm | Low 8 |
| 2 May | 9.2 °C | 19 % | 46 km/h | 0.0 mm | Moderate 12 |
| 3 May | 13.2 °C | 20 % | 33 km/h | 0.0 mm | Moderate 12 |
| 4 May | 14.9 °C | 19 % | 40 km/h | 0.0 mm | Moderate 15 |
| 5 May | 13.7 °C | 20 % | 37 km/h | 0.0 mm | Moderate 15 |
| 6 May | 15.0 °C | 19 % | 27 km/h | 0.1 mm | Moderate 14 |
| 7 May | 15.0 °C | 28 % | 47 km/h | 0.2 mm | Moderate 18 |
| 8 May | 14.4 °C | 10 % | 34 km/h | 0.0 mm | Moderate 19 |
| 9 May | 18.4 °C | 19 % | 31 km/h | 0.0 mm | Moderate 19 |
| 10 May | 22.6 °C | 22 % | 41 km/h | 0.0 mm | High 22 |
| 11 May | 24.4 °C | 23 % | 42 km/h | 0.0 mm | High 22 |
| 12 May | 15.3 °C | 59 % | 45 km/h | 12.3 mm | Very low 0 |
| 13 May | 9.7 °C | 34 % | 43 km/h | 0.4 mm | Very low 2 |
| 14 May | 14.7 °C | 32 % | 45 km/h | 0.8 mm | Very low 5 |
| 15 May | 11.1 °C | 26 % | 30 km/h | 0.2 mm | Low 8 |
| 16 May after | 8.7 °C | 25 % | 55 km/h | 0.2 mm | Moderate 12 |
| 17 May after | 10.2 °C | 21 % | 37 km/h | 0.6 mm | Low 11 |
| 18 May after | 14.7 °C | 22 % | 46 km/h | 0.0 mm | Moderate 16 |
| 19 May after | 18.4 °C | 37 % | 22 km/h | 2.5 mm | Very low 2 |
Its twins: fires that started in the same weather
It started with an FWI of 14.7, a minimum humidity of 18% and 3 days without rain. Fires in the area that started in weather like this since 2016: 16.
FWI at the start
14.7
Minimum humidity
18 %
Days without rain
3
this fire
chosen twins
rest of the area
Almost identicalSimilar
Outlines of the closest twins
This fire · Yero'o fire, April 2025
7,017 ha
17 days
FWI 14.7
Min. humidity 18 %
Yero'o fire, May 2018
3,690 ha
4 days
FWI 11.0
Min. humidity 18 %
12 km away, in 2018
First rain (1 mm or more) after it ended: 8.0 mm on 2 Jun.
Altanbulag fire, April 2017
6,873 ha
4 days
FWI 13.1
Min. humidity 17 %
106 km away, in 2017
First rain (1 mm or more) after it ended: 7.2 mm on 16 Apr.
Yero'o fire, May 2018
9,021 ha
9 days
FWI 12.0
Min. humidity 21 %
13 km away, in 2018
First rain (1 mm or more) after it ended: 7.3 mm on 26 May.
Yero'o fire, May 2025
3,489 ha
7 days
FWI 19.6
Min. humidity 18 %
9 km away, in 2025
First rain (1 mm or more) after it ended: 2.3 mm on 30 May.
Yero'o fire, June 2017
3,475 ha
7 days
FWI 18.8
Min. humidity 20 %
64 km away, in 2017
First rain (1 mm or more) after it ended: 2.9 mm on 1 Jul.
What happened to them
- 7 days
- median duration
- 3,726 ha
- median area
- 12 %
- went past 10,000 ha
- 2.7 mm
- rain at the end (median; 15 of 16 had it)
It was 1.9 times larger than the median of its twins and lasted 17 days, against 7 days.
Only 4 of its 16 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 1 of 16, 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 2.7 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
2.5 mmfirst rain
19 May4 days after it ended
68km/h · max. gust
It was considered over on 15 May, and on 19 May 2.5 mm fell. We do not know whether the rain or the firefighters put it out. Twins with rain when they ended: 15 of 16, with a median of 2.7 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.
Before and after, from space
Drag the line to compare the same ground before the fire and after it.
↔
Before · 22 Apr 2025
After · 22 May 2025
Sentinel-2 did not pass over on that day. Try another date, or use false colour, which is daily.
If the day is cloudy, change the date: each satellite passes once a day. In false colour the burnt ground looks brown or red.
The smoke
CAMS · CopernicusOn 11 May 2025 the air beside the fire reached 241 µg/m³ of PM2.5. That day averaged 116: 7.7 times the WHO daily guideline (15).
PM2.5 peak241 µg/m³
Days over the guideline9 days
PM10256 µg/m³
Optical depth1.14
WHO 15
27 Apr1 May5 May9 May13 May
Good
Fair
Moderate
Poor
Very poor
Extremely poor
Particles from the Copernicus CAMS model at the centre of the perimeter; these are not measurements in each town. The pale bar is the worst hour, the solid one the daily average.
Open-Meteo.com (CC BY 4.0) · Copernicus Atmosphere Monitoring Service (CAMS)
Detections table · 582Every 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
Frequently asked questions
- How long did the Yero'o fire last?
- According to the heat detections seen by satellite inside the perimeter, it burned from 29 April 2025 to 15 May 2025 (17 days). The perimeter dates it from 29 April 2025 to 11 May 2025.
- How much area did it burn?
- The perimeter GWIS (Copernicus) rebuilt from heat detections is 7,017 hectares (70.2 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire only entered Yero'o (6,965 ha, 0.8 %).
- What was the weather like?
- During the fire the temperature reached 24.4 °C, humidity dropped to 10 % and gusts hit 68 km/h. The fire danger index (FWI) reached 22, class High.
- Where does this data come from?
- From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Mongolia (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: 16. Their median duration was 7 days and their median area 3,726 ha; 12 % went past 10,000 ha. Only 4 of its 16 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 1 of 16, 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 2.7 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: 105 · 101 · 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.
- Last day with fire: 11 May 2025 → 15 May 2025.
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
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 29 April 2025 to 11 May 2025. 582 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 2025, 100 m cells), summed inside the perimeter: an estimate of what was there, not a damage count.
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.