How long did the Ust-Aldansky Ulus fire last?

According to the heat detections seen by satellite inside the perimeter, it burned from 4 September 2020 to 25 September 2020 (22 days). The perimeter dates it from 7 September 2020 to 25 September 2020.

How much area did it burn?

The perimeter GWIS (Copernicus) rebuilt from heat detections is 5,696 hectares (57.0 km²). It is an estimate: official national figures may differ.

Which municipalities burned?

The fire only entered Ust-Aldansky Ulus (5,755 ha, 0.3 %).

What was the weather like?

During the fire the temperature reached 21.6 °C, humidity dropped to 30 % and gusts hit 52 km/h. The fire danger index (FWI) reached 16, class Moderate.

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.

RU · Russia · 2020-09-04 → 2020-09-25

Ust-Aldansky Ulus fire, 4 September 2020 Ust-Aldansky Ulus

Out · last detection 25 Sept 2020, 18:47 UTC

The fire started on 4 September 2020 in Ust-Aldansky Ulus, Russia, and satellites saw it burning for 22 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 5,696 hectares from heat detections, spread across a single municipality.

It is the 841th largest in Sakha Republic since 2016 (of 1422 with a page). Number 288 in Russia in 2020, of 592.

Compare with…

Suggestions: Ust-Aldansky Ulus · 2017 Ust-Aldansky Ulus · 2017 Ust-Aldansky Ulus · 2020 Ust-Aldansky Ulus · 2020

Burnt area: 5,696ha; GWIS perimeter (Copernicus)
Duration: 22days; 4 Sept 2020 – 25 Sept 2020
Municipalities hit: 1; districts
Started on: 4 Sept; 2020
Heat detections: 683; in a single hotspot: 81 MW
Danger at start: 7; Low · FWI index
Average daily power: 245MW; detected power per day, on average

HOTSPOTS BY DAY 4 Sept25 Sept

Play back 25 Sept 2020

How it evolved, day by day

4 Sept 7 Sept 10 Sept 13 Sept 17 Sept 20 Sept 25 Sept

Fire radiative power detected each day, in megawatts, and number of hotspots. The magenta bar marks the peak day.

The weather it burned in

22°high

52km/h · peak gust

30%lowest humidity

It had gone 0 days without rain (1 mm or more) when it started. Rain came after the fire: 3.2 mm on 26 Sept.

This area had burned before

2% of the perimeter overlaps earlier fires recorded since 2016: 139 ha in 2017.

56 ha Ust-Aldansky Ulus fire, June 2017 23,725 ha in total; the hectares shown are those it shares with this fire

How big is it?

It burned the equivalent of 3.6% of the area of London (57 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

Ust-Aldansky Ulus where it started

5,755 ha reached on 4 Sept

0.3 %

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)
4 Sept	21.1 °C	45 %	38 km/h	0.0 mm	Low 7
5 Sept	21.6 °C	38 %	24 km/h	0.0 mm	Low 11
6 Sept	19.2 °C	54 %	18 km/h	2.0 mm	Very low 3
7 Sept	17.6 °C	44 %	23 km/h	0.4 mm	Low 6
8 Sept	16.7 °C	39 %	19 km/h	0.0 mm	Low 9
9 Sept	17.9 °C	38 %	18 km/h	0.0 mm	Moderate 12
10 Sept	18.1 °C	37 %	18 km/h	0.0 mm	Moderate 13
11 Sept	19.6 °C	33 %	25 km/h	0.0 mm	Moderate 15
12 Sept	18.4 °C	39 %	24 km/h	0.0 mm	Moderate 16
13 Sept	19.7 °C	32 %	32 km/h	1.5 mm	Low 10
14 Sept	12.8 °C	61 %	52 km/h	4.4 mm	Very low 2
15 Sept	12.9 °C	59 %	25 km/h	0.0 mm	Very low 3
16 Sept	15.4 °C	42 %	16 km/h	0.0 mm	Very low 5
17 Sept	16.0 °C	36 %	17 km/h	0.0 mm	Low 8
18 Sept	15.9 °C	39 %	14 km/h	0.0 mm	Low 10
19 Sept	17.0 °C	30 %	19 km/h	0.0 mm	Moderate 13
20 Sept	15.8 °C	44 %	12 km/h	0.0 mm	Moderate 12
21 Sept	14.5 °C	49 %	13 km/h	0.0 mm	Moderate 12
22 Sept	12.3 °C	56 %	10 km/h	0.0 mm	Low 10
23 Sept	13.8 °C	47 %	15 km/h	0.0 mm	Low 10
24 Sept	15.2 °C	35 %	17 km/h	0.0 mm	Moderate 13
25 Sept	14.7 °C	38 %	28 km/h	0.0 mm	Moderate 15
26 Sept after	10.1 °C	48 %	41 km/h	3.2 mm	Very low 3

Before and after, from space

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

↔

Before · 28 Aug 2020

After · 2 Oct 2020

Before After

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 · 683Every 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

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 4 September 2020 to 25 September 2020 (22 days). The perimeter dates it from 7 September 2020 to 25 September 2020.
How much area did it burn?: The perimeter GWIS (Copernicus) rebuilt from heat detections is 5,696 hectares (57.0 km²). It is an estimate: official national figures may differ.
Which municipalities burned?: The fire only entered Ust-Aldansky Ulus (5,755 ha, 0.3 %).
What was the weather like?: During the fire the temperature reached 21.6 °C, humidity dropped to 30 % and gusts hit 52 km/h. The fire danger index (FWI) reached 16, class Moderate.
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

NASA FIRMS ↗
GWIS · Copernicus ↗

History of this page · 1 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.

25 October 2026 Start date: 7 September 2020 → 4 September 2020.

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.

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What really happened?

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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 adjusted with the VIIRS detections inside the perimeter, which said 7 September 2020 to 25 September 2020. 683 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.

Where it burned