Burned area
satellite only11,777ha
Perimeter published by GWIS (Copernicus).
- Source
- GWIS (Copernicus)
- Date
- 4 Aug 2021 – 16 Aug 2021
+− cross-check
No official record is matched to this page to compare it with.
RU · Russia · –
Khangalassky Ulus fire, 4 August 2021 Khangalassky Ulus
Out · last detection 16 Aug 2021, 03:26 UTC
The fire started on 4 August 2021 in Khangalassky Ulus, Russia, and satellites saw it burning for 13 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 11,777 hectares from heat detections, spread across a single municipality.
It is the 396th largest in Sakha Republic since 2016 (of 1347 with a page). Number 146 in Russia in 2021, of 581.
Use this data
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Use this data
Fire page data · version 2026-10-27matches 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 only13days
4 Aug 2021 to 16 Aug 2021: first and last day with fire on the page.
- Source
- GWIS (Copernicus) · NASA FIRMS · VIIRS
- Date
- last detection: 16 Aug 2021, 03:26 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 only4 Aug 2021
First day with fire seen by the satellites or the perimeter.
- Source
- GWIS (Copernicus) · NASA FIRMS · VIIRS
- Date
- 4 Aug 2021
+− cross-check
No official record is matched to this page, so the alert time and the cause are not known here.
The worst day
satellite only5,608MW
Total radiative power on 10 August 2021; hotspots that day: 368.
- Source
- NASA FIRMS · VIIRS (FRP)
- Date
- 10 Aug 2021
+− 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
model10.3FWI · low
Fire Weather Index (Canadian system) computed by WorldFires for the day the fire started. Consecutive days without rain before: 0.
- Source
- WorldFires calculation (Canadian FWI system)
- Date
- 4 Aug 2021, 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
model29.5°C · 34% RH
High of 29.5 °C and minimum humidity of 34% on 10 August 2021; gusts of 52 km/h on 7 August 2021.
- Source
- weather model at the fire’s grid cell
- Date
- 4 Aug 2021 – 16 Aug 2021
- 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
-
logStart date: 28 July 2021 → 4 August 2021.
-
· reconstructed weatherWeather and FWI computed from the ERA5 reanalysis
-
logStart date: 4 August 2021 → 28 July 2021.
-
· reconstructed GHSLPopulation and built-up area computed
Area logged each night
Move the slider to see which area the page published each day.
Versioned permanent link
https://worldfires.org/en/fire/khangalassky-ulus-2021-08-2?v=2026-10-27A 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 khangalassky-ulus-2021-08-2.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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 2021-08-04 | 5 | 5 | 23.8 | 12.9 | 53 | 15.2 | 36.4 | 0 | 10.3 | bajo | 1 |
| 2021-08-05 | 76 | 242 | 25.5 | 11.5 | 36 | 12.3 | 32.4 | 0 | 15 | moderado | 1 |
| 2021-08-06 | 48 | 322 | 25.1 | 11.3 | 38 | 16.2 | 38.2 | 0 | 18.1 | moderado | 1 |
| 2021-08-07 | 178 | 641 | 24 | 16.1 | 41 | 22.6 | 52.2 | 0.1 | 22 | alto | 1 |
| 2021-08-08 | 310 | 1,561 | 26.5 | 14.1 | 44 | 17.2 | 40.7 | 0 | 19.6 | moderado | 1 |
| 2021-08-09 | 286 | 1,088 | 27.2 | 13.6 | 47 | 13 | 30.2 | 0 | 17.9 | moderado | 1 |
| 2021-08-10 | 368 | 5,608 | 29.5 | 11.6 | 34 | 9.2 | 24.8 | 0 | 18.8 | moderado | 1 |
| 2021-08-11 | 646 | 4,592 | 28.2 | 14.8 | 45 | 7.9 | 21.2 | 0 | 18 | moderado | 1 |
| 2021-08-12 | 247 | 803 | 26 | 13.3 | 51 | 8.4 | 22 | 0 | 16.3 | moderado | 1 |
| 2021-08-13 | 192 | 514 | 25.4 | 13.1 | 53 | 8.4 | 15.1 | 0 | 15.5 | moderado | 1 |
| 2021-08-14 | 366 | 2,455 | 29 | 13.8 | 35 | 10.2 | 25.9 | 0 | 19.9 | moderado | 1 |
| 2021-08-15 | 331 | 2,380 | 29 | 14 | 46 | 10.1 | 35.3 | 0.4 | 20.1 | moderado | 1 |
| 2021-08-16 | 59 | 528 | 28 | 14.9 | 45 | 7.4 | 32.8 | 1 | 12.1 | moderado | 1 |
| 2021-08-17 | 0 | 0 | 23.7 | 15.1 | 58 | 17.6 | 37.4 | 9.6 | 2 | 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
- 11,777ha
- GWIS perimeter (Copernicus)
- Duration
- 13days
- 4 Aug 2021 – 16 Aug 2021
- Municipalities hit
- 1
- districts
- Started on
- 4 Aug
- 2021
- Heat detections
- 3,112
- in a single hotspot: 0 MW
- Danger at start
- 10
- Low · FWI index
- Average daily power
- 1.6GW
- detected power per day, on average
Where it burned
HOTSPOTS BY DAY
4 Aug16 Aug
16 Aug 2021
How it evolved, day by day
4 Aug
7 Aug
10 Aug
13 Aug
16 Aug
Fire radiative power detected each day, in megawatts, and number of hotspots. The magenta bar marks the peak day.
The weather it burned in
30°high
52km/h · peak gust
34%lowest humidity
It had gone 0 days without rain (1 mm or more) when it started. Rain came after the fire: 9.6 mm on 17 Aug.
This area had burned before
5% of the perimeter overlaps earlier fires recorded since 2016: 558 ha in 2019.
How big is it?
London boundary: geoBoundaries · Office for National Statistics (Open Government Licence v3.0).
Moscow boundary: geoBoundaries · OpenStreetMap, Wambacher · © OpenStreetMap contributors (ODbL 1.0).
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).
This compares size, not location: both shapes are at the same scale, north up, centred on each other.
What happened to each town
-
Khangalassky Ulus where it started11,702 ha0.5 %
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 2020Built-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) |
|---|---|---|---|---|---|
| 4 Aug | 23.8 °C | 53 % | 36 km/h | 0.0 mm | Low 10 |
| 5 Aug | 25.5 °C | 36 % | 32 km/h | 0.0 mm | Moderate 15 |
| 6 Aug | 25.1 °C | 38 % | 38 km/h | 0.0 mm | Moderate 18 |
| 7 Aug | 24.0 °C | 41 % | 52 km/h | 0.1 mm | High 22 |
| 8 Aug | 26.5 °C | 44 % | 41 km/h | 0.0 mm | Moderate 20 |
| 9 Aug | 27.2 °C | 47 % | 30 km/h | 0.0 mm | Moderate 18 |
| 10 Aug | 29.5 °C | 34 % | 25 km/h | 0.0 mm | Moderate 19 |
| 11 Aug | 28.2 °C | 45 % | 21 km/h | 0.0 mm | Moderate 18 |
| 12 Aug | 26.0 °C | 51 % | 22 km/h | 0.0 mm | Moderate 16 |
| 13 Aug | 25.4 °C | 53 % | 15 km/h | 0.0 mm | Moderate 16 |
| 14 Aug | 29.0 °C | 35 % | 26 km/h | 0.0 mm | Moderate 20 |
| 15 Aug | 29.0 °C | 46 % | 35 km/h | 0.4 mm | Moderate 20 |
| 16 Aug | 28.0 °C | 45 % | 33 km/h | 1.0 mm | Moderate 12 |
| 17 Aug after | 23.7 °C | 58 % | 37 km/h | 9.6 mm | Very low 2 |
Its twins: fires that started in the same weather
It started with an FWI of 10.3, a minimum humidity of 53% and rain the day before. Fires in the area that started in weather like this since 2017: 1.
FWI at the start
10.3
Minimum humidity
53 %
Days without rain
0
this fire
chosen twins
rest of the area
Almost identicalSimilar
Outlines of the closest twins
This fire · Khangalassky Ulus fire, 4 August 2021
11,777 ha
13 days
FWI 10.3
Min. humidity 53 %
Khangalassky Ulus fire, August 2017
3,396 ha
6 days
FWI 3.4
Min. humidity 53 %
42 km away, in 2017
First rain (1 mm or more) after it ended: 2.4 mm on 16 Aug.
What happened to them
Fires in the area that started in similar weather: 1. With fewer than 15 we give no figures: they would be more noise than signal.
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
9.6 mmfirst rain
17 Augthe day after it ended
52km/h · max. gust
It was considered over on 16 Aug, and on 17 Aug 9.6 mm fell. We do not know whether the rain or the firefighters put it out.
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 2017.
- 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 · 28 Jul 2021
After · 23 Aug 2021
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.
Detections table · 0Every 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 Khangalassky Ulus fire last?
- GWIS (Copernicus) dates it between 4 August 2021 and 16 August 2021: 13 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 11,777 hectares (117.8 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire only entered Khangalassky Ulus (11,702 ha, 0.5 %).
- What was the weather like?
- During the fire the temperature reached 29.5 °C, humidity dropped to 34 % and gusts hit 52 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 Russia (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: 112 · 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.
- Start date: 28 July 2021 → 4 August 2021.
- Start date: 4 August 2021 → 28 July 2021.
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 from the perimeter: the VIIRS detections inside it did not change them. No 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.
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 (Open Data Commons Open Database License 1.0). 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.