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Ust-Aldansky Ulus fire, 31 July 2021 Ust-Aldansky Ulus

Out · last detection 14 Aug 2021, 17:51 UTC

The fire started on 31 July 2021 in Ust-Aldansky Ulus, Russia, and satellites saw it burning for 15 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 6,757 hectares from heat detections, spread across a single municipality.

It is the 735th largest in Sakha Republic since 2016 (of 1422 with a page). Number 272 in Russia in 2021, of 581.

Compare with…

Suggestions: Ust-Aldansky Ulus · 2019Ust-Aldansky Ulus · 2021Ust-Aldansky Ulus · 2021Ust-Aldansky Ulus · 2017

Burnt area
6,757ha
GWIS perimeter (Copernicus)
Duration
15days
31 Jul 2021 – 14 Aug 2021
Municipalities hit
1
districts
Started on
31 Jul
2021
Heat detections
1,318
in a single hotspot: 625 MW
Danger at start
18
Moderate · FWI index
Average daily power
2.3GW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 31 Jul14 Aug
14 Aug 2021

How it evolved, day by day

31 Jul 2021 · 10 MW · 3 1 Aug 2021 · 25 MW · 9 2 Aug 2021 · 748 MW · 74 3 Aug 2021 · 169 MW · 23 4 Aug 2021 · 2 MW · 3 5 Aug 2021 · 1,015 MW · 78 6 Aug 2021 · 233 MW · 58 7 Aug 2021 · 1,474 MW · 90 8 Aug 2021 · 2,273 MW · 180 9 Aug 2021 · 2,558 MW · 105 10 Aug 2021 · 23,452 MW · 688 11 Aug 2021 · 1 MW · 1 13 Aug 2021 · 2 MW · 2 14 Aug 2021 · 3 MW · 4
31 Jul 2 Aug 4 Aug 6 Aug 8 Aug 10 Aug 13 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
51km/h · peak gust
13%lowest humidity

It had gone 5 days without rain (1 mm or more) when it started. Rain came after the fire: 4.1 mm on 14 Aug.

This area had burned before

6% of the perimeter overlaps earlier fires recorded since 2016: 400 ha in 2019.

How big is it?

10 km
It burned the equivalent of 4.3% of the area of London (68 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. Ust-Aldansky Ulus where it started
    6,732 ha reached on 31 Jul
    0.4 %

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 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)
31 Jul 26.3 °C 27 % 18 km/h 0.0 mm Moderate 18
1 Aug 30.2 °C 30 % 26 km/h 0.0 mm Moderate 21
2 Aug 29.5 °C 13 % 41 km/h 0.0 mm High 32
3 Aug 27.9 °C 27 % 36 km/h 0.0 mm High 28
4 Aug 28.6 °C 23 % 19 km/h 0.0 mm High 25
5 Aug 26.5 °C 17 % 36 km/h 0.0 mm High 31
6 Aug 26.4 °C 26 % 37 km/h 0.0 mm High 30
7 Aug 26.4 °C 26 % 51 km/h 0.0 mm High 35
8 Aug 26.3 °C 16 % 41 km/h 0.0 mm High 34
9 Aug 28.7 °C 17 % 30 km/h 0.0 mm High 30
10 Aug 30.0 °C 15 % 28 km/h 0.0 mm High 33
11 Aug 28.7 °C 34 % 26 km/h 0.6 mm High 26
12 Aug 23.4 °C 51 % 25 km/h 1.3 mm Low 9
13 Aug 24.4 °C 49 % 23 km/h 0.0 mm Moderate 13
14 Aug 25.3 °C 49 % 26 km/h 4.1 mm Very low 4

Before and after, from space

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

Before · 24 Jul 2021
After · 21 Aug 2021

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 · 1,318Every 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 Ust-Aldansky Ulus fire last?
According to the heat detections seen by satellite inside the perimeter, it burned from 31 July 2021 to 14 August 2021 (15 days). The perimeter dates it from 31 July 2021 to 13 August 2021.
How much area did it burn?
The perimeter GWIS (Copernicus) rebuilt from heat detections is 6,757 hectares (67.6 km²). It is an estimate: official national figures may differ.
Which municipalities burned?
The fire only entered Ust-Aldansky Ulus (6,732 ha, 0.4 %).
What was the weather like?
During the fire the temperature reached 30.2 °C, humidity dropped to 13 % and gusts hit 51 km/h. The fire danger index (FWI) reached 35, 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 · 1 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.
  1. Last day with fire: 13 August 2021 → 14 August 2021.

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
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 112.

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 31 July 2021 to 13 August 2021. 1,318 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 (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.