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Aldansky Ulus fire, 27 July 2023 Aldansky Ulus

Out · last detection 10 Aug 2023, 17:40 UTC

The fire started on 27 July 2023 in Aldansky Ulus, Russia, and satellites saw it burning for 15 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 16,508 hectares from heat detections, spread across a single municipality.

It is the 323th largest in Sakha Republic since 2016 (of 1422 with a page). Number 51 in Russia in 2023, of 450.

Compare with…

Suggestions: Aldansky Ulus · 2024Aldansky Ulus · 2022Aldansky Ulus · 2024Aldansky Ulus · 2018

Burnt area
16,508ha
GWIS perimeter (Copernicus)
Duration
15days
27 Jul 2023 – 10 Aug 2023
Municipalities hit
1
districts
Started on
27 Jul
2023
Heat detections
1,762
in a single hotspot: 123 MW
Danger at start
17
Moderate · FWI index
Average daily power
736MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 27 Jul10 Aug
10 Aug 2023

How it evolved, day by day

28 Jul 2023 · 609 MW · 32 29 Jul 2023 · 52 MW · 12 30 Jul 2023 · 358 MW · 136 31 Jul 2023 · 1,095 MW · 191 1 Aug 2023 · 61 MW · 15 2 Aug 2023 · 12 MW · 3 3 Aug 2023 · 29 MW · 12 4 Aug 2023 · 153 MW · 46 5 Aug 2023 · 1,130 MW · 144 6 Aug 2023 · 754 MW · 150 7 Aug 2023 · 615 MW · 176 8 Aug 2023 · 3,988 MW · 532 9 Aug 2023 · 1,182 MW · 242 10 Aug 2023 · 269 MW · 63
28 Jul 30 Jul 1 Aug 3 Aug 5 Aug 7 Aug 8 Aug 9 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

29°high
43km/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: 1.7 mm on 14 Aug.

This area had burned before

2% of the perimeter overlaps earlier fires recorded since 2016: 407 ha in 2019.

How big is it?

10 km
It burned the equivalent of 10% of the area of London (165 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. Aldansky Ulus where it started
    16,561 ha
    0.1 %

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 2025
Built-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)

Day High Min. humidity Peak gust Rain Danger (FWI)
27 Jul 29.3 °C 28 % 23 km/h 0.0 mm Moderate 17
28 Jul 28.5 °C 24 % 31 km/h 0.0 mm Moderate 21
29 Jul 27.4 °C 29 % 27 km/h 0.0 mm Moderate 21
30 Jul 28.1 °C 27 % 34 km/h 0.0 mm High 24
31 Jul 28.4 °C 22 % 24 km/h 0.0 mm High 25
1 Aug 19.7 °C 36 % 36 km/h 0.0 mm High 23
2 Aug 18.1 °C 55 % 43 km/h 4.4 mm Very low 2
3 Aug 22.0 °C 40 % 18 km/h 0.2 mm Very low 5
4 Aug 25.1 °C 32 % 16 km/h 0.0 mm Moderate 13
5 Aug 28.2 °C 26 % 15 km/h 0.0 mm Moderate 18
6 Aug 29.1 °C 23 % 12 km/h 0.0 mm Moderate 20
7 Aug 29.1 °C 30 % 19 km/h 0.1 mm High 24
8 Aug 25.2 °C 21 % 26 km/h 0.0 mm High 26
9 Aug 24.9 °C 39 % 31 km/h 0.0 mm High 22
10 Aug 23.3 °C 57 % 30 km/h 0.5 mm Moderate 17
11 Aug after 29.7 °C 35 % 25 km/h 0.1 mm Moderate 19
12 Aug after 28.6 °C 40 % 27 km/h 0.0 mm High 22
13 Aug after 27.1 °C 34 % 47 km/h 0.0 mm High 27
14 Aug after 21.5 °C 49 % 37 km/h 1.7 mm Low 9

Before and after, from space

Drag the line to compare the same ground before the fire and after it.

Before · 20 Jul 2023
After · 17 Aug 2023

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 · Copernicus

On 10 August 2023 the air beside the fire reached 969 µg/m³ of PM2.5. That day averaged 415: 28 times the WHO daily guideline (15).

PM2.5 peak969 µg/m³
Days over the guideline17 days
PM101,382 µg/m³
Optical depth6.08
2526272829303112345678910111213
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 · 1,762Every 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 Russia ›

Frequently asked questions

How long did the Aldansky Ulus fire last?
GWIS (Copernicus) dates it between 27 July 2023 and 10 August 2023: 15 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 16,508 hectares (165.1 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire only entered Aldansky Ulus (16,561 ha, 0.1 %).
What was the weather like?
During the fire the temperature reached 29.3 °C, humidity dropped to 21 % and gusts hit 43 km/h. The fire danger index (FWI) reached 26, 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 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.

No changes since 24 October 2026.

RSS Changes to this page

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
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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 112.

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. 1,762 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.

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 (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.