Burned area
satellite only3,761ha
Perimeter published by GWIS (Copernicus).
- Source
- GWIS (Copernicus)
- Date
- 30 Jun 2023 – 15 Jul 2023
+− cross-check
No official record is matched to this page to compare it with.
RU · Russia · –
Ust-Maysky Ulus fire, 30 June 2023 Ust-Maysky Ulus
Out · last detection 15 Jul 2023, 01:59 UTC
The fire started on 30 June 2023 in Ust-Maysky Ulus, Russia, and satellites saw it burning for 16 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 3,761 hectares from heat detections, spread across a single municipality.
It is the 1115th largest in Sakha Republic since 2016 (of 1347 with a page). Number 332 in Russia in 2023, of 450.
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Suggestions: Ust-Maysky Ulus · 2023Tomponsky Ulus · 2021
Use this data
Fire page data · version 2026-10-25matches 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 only16days
30 Jun 2023 to 15 Jul 2023: first and last day with fire on the page.
- Source
- GWIS (Copernicus) · NASA FIRMS · VIIRS
- Date
- last detection: 15 Jul 2023, 01:59 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 only30 Jun 2023
First day with fire seen by the satellites or the perimeter.
- Source
- GWIS (Copernicus) · NASA FIRMS · VIIRS
- Date
- 30 Jun 2023
+− cross-check
No official record is matched to this page, so the alert time and the cause are not known here.
Hotspots
satellite only373
VIIRS detections at 375 m. Most intense hotspot: 211 MW.
- Source
- NASA FIRMS · VIIRS (Suomi NPP)
- Date
- 30 Jun 2023 – 15 Jul 2023
+− 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 only2,480MW
Total radiative power on 3 July 2023; hotspots that day: 88.
- Source
- NASA FIRMS · VIIRS (FRP)
- Date
- 3 Jul 2023
+− 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
model9.4FWI · low
Fire Weather Index (Canadian system) computed by WorldFires for the day the fire started. Consecutive days without rain before: 1.
- Source
- WorldFires calculation (Canadian FWI system)
- Date
- 30 Jun 2023, 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
model28.4°C · 32% RH
High of 28.4 °C and minimum humidity of 32% on 3 July 2023; gusts of 52 km/h on 9 July 2023.
- Source
- weather model at the fire’s grid cell
- Date
- 30 Jun 2023 – 15 Jul 2023
- 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: 10 July 2023 → 15 July 2023.
-
· reconstructed GHSLPopulation and built-up area computed
What was saved on 25 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
- 3,761 ha
- Dates
- 30 Jun 2023 – 15 Jul 2023
- Name
- Ust-Maysky Ulus
- Official record
- —
Versioned permanent link
https://worldfires.org/en/fire/ust-maysky-ulus-2023-06-8?v=2026-10-25A 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 ust-maysky-ulus-2023-06-8.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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 2023-06-30 | 10 | 28 | 24.6 | 9.5 | 37 | 7.6 | 18.7 | 0 | 9.4 | bajo | 1 |
| 2023-07-01 | 22 | 244 | 26.2 | 10.1 | 35 | 8.4 | 22 | 0 | 12.6 | moderado | 1 |
| 2023-07-02 | 26 | 201 | 26.5 | 10.1 | 38 | 7.9 | 21.6 | 0 | 12.9 | moderado | 1 |
| 2023-07-03 | 88 | 2,480 | 28.4 | 12.4 | 32 | 15 | 36.7 | 0 | 18.7 | moderado | 1 |
| 2023-07-04 | 27 | 160 | 25.5 | 13.4 | 43 | 13.7 | 38.5 | 0.3 | 17.5 | moderado | 1 |
| 2023-07-05 | 9 | 34 | 23.4 | 12.2 | 48 | 13.1 | 34.6 | 0.1 | 15.7 | moderado | 1 |
| 2023-07-06 | 36 | 89 | 24.1 | 8.5 | 38 | 9 | 23.8 | 0 | 14.4 | moderado | 1 |
| 2023-07-07 | 90 | 1,223 | 23.6 | 8.3 | 30 | 11.6 | 28.8 | 0 | 17.8 | moderado | 1 |
| 2023-07-08 | 0 | 0 | 14.5 | 7.7 | 75 | 13.2 | 32 | 7.7 | 0.1 | muy_bajo | 1 |
| 2023-07-09 | 0 | 0 | 8.8 | 4.3 | 79 | 20.9 | 52.2 | 3.9 | 0 | muy_bajo | 1 |
| 2023-07-10 | 8 | 18 | 16.6 | 0.2 | 34 | 18.6 | 44.6 | 0 | 2.4 | muy_bajo | 1 |
| 2023-07-11 | 42 | 161 | 19.1 | 1.9 | 48 | 14.2 | 33.1 | 0 | 4.4 | muy_bajo | 1 |
| 2023-07-12 | 7 | 13 | 21 | 9.8 | 44 | 12.8 | 36 | 2.1 | 2.9 | muy_bajo | 1 |
| 2023-07-13 | 2 | 2 | 22 | 8.7 | 52 | 8.8 | 31 | 0.3 | 4.9 | muy_bajo | 1 |
| 2023-07-14 | 4 | 7 | 20.3 | 9.6 | 64 | 11.7 | 32.8 | 1.1 | 3.5 | muy_bajo | 1 |
| 2023-07-15 | 2 | 16 | 20.2 | 10.5 | 59 | 17.8 | 45.4 | 0.4 | 7.1 | bajo | 1 |
| 2023-07-16 | 0 | 0 | 15.2 | 5.6 | 78 | 16.4 | 41.4 | 22 | 0 | 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
- 3,761ha
- GWIS perimeter (Copernicus)
- Duration
- 16days
- 30 Jun 2023 – 15 Jul 2023
- Municipalities hit
- 1
- districts
- Started on
- 30 Jun
- 2023
- Heat detections
- 373
- in a single hotspot: 211 MW
- Danger at start
- 9
- Low · FWI index
- Average daily power
- 334MW
- detected power per day, on average
Where it burned
HOTSPOTS BY DAY
30 Jun15 Jul
15 Jul 2023
How it evolved, day by day
30 Jun
3 Jul
6 Jul
11 Jul
14 Jul
Fire radiative power detected each day, in megawatts, and number of hotspots. The magenta bar marks the peak day.
The weather it burned in
28°high
52km/h · peak gust
30%lowest humidity
It had gone one day without rain (1 mm or more) when it started. Rain came after the fire: 22.0 mm on 16 Jul.
This area had burned before
No earlier perimeters overlap this fire since 2016, when the satellite record begins.
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
-
Ust-Maysky Ulus where it started3,839 ha reached on 30 Jun0.0 %
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)
| Day | High | Min. humidity | Peak gust | Rain | Danger (FWI) |
|---|---|---|---|---|---|
| 30 Jun | 24.6 °C | 37 % | 19 km/h | 0.0 mm | Low 9 |
| 1 Jul | 26.2 °C | 35 % | 22 km/h | 0.0 mm | Moderate 13 |
| 2 Jul | 26.5 °C | 38 % | 22 km/h | 0.0 mm | Moderate 13 |
| 3 Jul | 28.4 °C | 32 % | 37 km/h | 0.0 mm | Moderate 19 |
| 4 Jul | 25.5 °C | 43 % | 38 km/h | 0.3 mm | Moderate 18 |
| 5 Jul | 23.4 °C | 48 % | 35 km/h | 0.1 mm | Moderate 16 |
| 6 Jul | 24.1 °C | 38 % | 24 km/h | 0.0 mm | Moderate 14 |
| 7 Jul | 23.6 °C | 30 % | 29 km/h | 0.0 mm | Moderate 18 |
| 8 Jul | 14.5 °C | 75 % | 32 km/h | 7.7 mm | Very low 0 |
| 9 Jul | 8.8 °C | 79 % | 52 km/h | 3.9 mm | Very low 0 |
| 10 Jul | 16.6 °C | 34 % | 45 km/h | 0.0 mm | Very low 2 |
| 11 Jul | 19.1 °C | 48 % | 33 km/h | 0.0 mm | Very low 4 |
| 12 Jul | 21.0 °C | 44 % | 36 km/h | 2.1 mm | Very low 3 |
| 13 Jul | 22.0 °C | 52 % | 31 km/h | 0.3 mm | Very low 5 |
| 14 Jul | 20.3 °C | 64 % | 33 km/h | 1.1 mm | Very low 4 |
| 15 Jul | 20.2 °C | 59 % | 45 km/h | 0.4 mm | Low 7 |
| 16 Jul after | 15.2 °C | 78 % | 41 km/h | 22.0 mm | Very low 0 |
Its twins: fires that started in the same weather
It started with an FWI of 9.4, a minimum humidity of 37% and 1 day without rain. Fires in the area that started in weather like this since 2016: 22.
FWI at the start
9.4
Minimum humidity
37 %
Days without rain
1
this fire
chosen twins
rest of the area
Almost identicalSimilar
Outlines of the closest twins
This fire · Ust-Maysky Ulus fire, 30 June 2023
3,761 ha
16 days
FWI 9.4
Min. humidity 37 %
Ust-Maysky Ulus fire, July 2023
12,583 ha
20 days
FWI 9.0
Min. humidity 37 %
197 km away, in 2023
First rain (1 mm or more) after it ended: 4.6 mm on 14 Aug.
Tomponsky Ulus fire, August 2021
7,741 ha
15 days
FWI 10.1
Min. humidity 36 %
141 km away, in 2021
First rain (1 mm or more) after it ended: 21.2 mm on 16 Aug.
Tattinsky Ulus fire, July 2020
35,561 ha
32 days
FWI 8.1
Min. humidity 37 %
230 km away, in 2020
First rain (1 mm or more) after it ended: 2.2 mm on 17 Aug.
Ust-Maysky Ulus fire, June 2021
3,992 ha
15 days
FWI 11.3
Min. humidity 37 %
202 km away, in 2021
First rain (1 mm or more) after it ended: 13.9 mm on 11 Jul.
Okhotsky Rayon fire, June 2021
3,484 ha
11 days
FWI 9.4
Min. humidity 36 %
239 km away, in 2021
First rain (1 mm or more) after it ended: 2.1 mm on 8 Jul.
What happened to them
- 15 days
- median duration
- 6,214 ha
- median area
- 27 %
- went past 10,000 ha
- 5.8 mm
- rain at the end (median; 22 of 22 had it)
It stayed below its twins: 3,761 ha against a median of 6,214 ha. It lasted 16 days, against 15 days.
All of them had rain in the ten days after the end: the first rainy day brought a median of 5.8 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
22.0 mmfirst rain
16 Julthe day after it ended
52km/h · max. gust
It was considered over on 15 Jul, and on 16 Jul 22.0 mm fell. We do not know whether the rain or the firefighters put it out. Twins with rain when they ended: 22 of 22, with a median of 5.8 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 · 23 Jun 2023
After · 22 Jul 2023
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 8 July 2023 the air beside the fire reached 82 µg/m³ of PM2.5. That day averaged 40: 2.7 times the WHO daily guideline (15).
PM2.5 peak82 µg/m³
Days over the guideline11 days
PM10118 µg/m³
Optical depth2.13
WHO 15
28 Jun2 Jul6 Jul10 Jul
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 · 373Every 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 |
|---|
Frequently asked questions
- How long did the Ust-Maysky Ulus fire last?
- According to the heat detections seen by satellite inside the perimeter, it burned from 30 June 2023 to 15 July 2023 (16 days). The perimeter dates it from 30 June 2023 to 10 July 2023.
- How much area did it burn?
- The perimeter GWIS (Copernicus) rebuilt from heat detections is 3,761 hectares (37.6 km²). It is an estimate: official national figures may differ.
- Which municipalities burned?
- The fire only entered Ust-Maysky Ulus (3,839 ha, 0.0 %).
- What was the weather like?
- During the fire the temperature reached 28.4 °C, humidity dropped to 30 % and gusts hit 52 km/h. The fire danger index (FWI) reached 19, 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.
- 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: 22. Their median duration was 15 days and their median area 6,214 ha; 27 % went past 10,000 ha. All of them had rain in the ten days after the end: the first rainy day brought a median of 5.8 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: 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.
- Last day with fire: 10 July 2023 → 15 July 2023.
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 30 June 2023 to 10 July 2023. 373 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 (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.