Burned area
satellite only494ha
Perimeter published by EFFIS (Copernicus).
- Source
- EFFIS (Copernicus)
- Date
- perimeter revised on 6 October 2023
+− cross-check
No official record is matched to this page to compare it with.
UA · Ukraine · –
Zviahel fire, September 2023 Звягель · Zviahel
Out · last detection 23 Sept 2023, 10:10 UTC
The fire started on 22 September 2023 in Zviahel, Ukraine, and satellites saw it burning for 4 days. Copernicus mapped a burnt perimeter of 494 hectares from satellite imagery, spread across a single municipality.
It is the 47th largest in Zhytomyr Oblast since 2016 (of 179 with a page). Number 72 in Ukraine in 2023, of 491.
The power measured by the satellite is low (7.6 MW in the strongest hotspot), more typical of grass or stubble burning, or a slow surface fire, than of a large crown fire.
Use this data
Compare with…
Use this data
Fire page data · version 2026-10-24matches 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 only4days
22 Sept 2023 to 25 Sept 2023: first and last day with fire on the page.
- Source
- EFFIS (Copernicus) · NASA FIRMS · VIIRS
- Date
- last detection: 23 Sept 2023, 10:10 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 only22 Sept 2023
First day with fire seen by the satellites or the perimeter.
- Source
- EFFIS (Copernicus) · NASA FIRMS · VIIRS
- Date
- 22 Sept 2023
+− cross-check
No official record is matched to this page, so the alert time and the cause are not known here.
Hotspots
satellite only10
VIIRS detections at 375 m. Most intense hotspot: 8 MW.
- Source
- NASA FIRMS · VIIRS (Suomi NPP)
- Date
- 22 Sept 2023 – 25 Sept 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 only25MW
Total radiative power on 23 September 2023; hotspots that day: 7.
- Source
- NASA FIRMS · VIIRS (FRP)
- Date
- 23 Sept 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
model31.3FWI · high
Fire Weather Index (Canadian system) computed by WorldFires for the day the fire started. Consecutive days without rain before: 2.
- Source
- WorldFires calculation (Canadian FWI system)
- Date
- 22 Sept 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
model27.2°C · 52% RH
High of 27.2 °C and minimum humidity of 52% on 23 September 2023; gusts of 44 km/h on 22 September 2023.
- Source
- weather model at the fire’s grid cell
- Date
- 22 Sept 2023 – 25 Sept 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
-
· reconstructed perimeterEFFIS (Copernicus) revises the perimeter
What was saved on 24 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
- 494 ha
- Dates
- 22 Sept 2023 – 25 Sept 2023
- Name
- Zviahel
- Official record
- —
Versioned permanent link
https://worldfires.org/en/fire/zviahel-2023-09?v=2026-10-24A 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 zviahel-2023-09.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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 2023-09-22 | 3 | 11 | 27 | 14.2 | 33 | 23 | 44.3 | 0.2 | 31.3 | alto | 1 |
| 2023-09-23 | 7 | 25 | 27.2 | 16.8 | 52 | 19.9 | 40 | 0 | 28.5 | alto | 1 |
| 2023-09-24 | 0 | 0 | 25.8 | 16.2 | 58 | 15.6 | 29.2 | 0 | 18.7 | moderado | 1 |
| 2023-09-25 | 0 | 0 | 23.5 | 15.3 | 60 | 17.8 | 33.8 | 0 | 19.4 | moderado | 1 |
| 2023-09-26 | 0 | 0 | 23.2 | 13.1 | 60 | 12.7 | 23 | 0 | 16.9 | moderado | 0 |
| 2023-09-27 | 0 | 0 | 24.4 | 12.2 | 53 | 10.5 | 20.2 | 0 | 16.1 | moderado | 0 |
| 2023-09-28 | 0 | 0 | 24.8 | 8.7 | 37 | 8.8 | 18.4 | 0 | 20.3 | moderado | 0 |
| 2023-09-29 | 0 | 0 | 26.3 | 9 | 27 | 7.7 | 18.7 | 0 | 27 | alto | 0 |
| 2023-09-30 | 0 | 0 | 26.1 | 8.4 | 31 | 13 | 29.5 | 0 | 30.8 | alto | 0 |
| 2023-10-01 | 0 | 0 | 18.1 | 11.3 | 46 | 18.9 | 39.6 | 0.7 | 25.4 | alto | 0 |
| 2023-10-02 | 0 | 0 | 17.8 | 7.8 | 44 | 17.6 | 35.6 | 0 | 25.8 | alto | 0 |
| 2023-10-03 | 0 | 0 | 22.1 | 9.3 | 41 | 18.8 | 36 | 0 | 28 | alto | 0 |
| 2023-10-04 | 0 | 0 | 19 | 10.9 | 45 | 23.9 | 47.2 | 0.5 | 35.5 | alto | 0 |
| 2023-10-05 | 0 | 0 | 17.9 | 7.2 | 45 | 21.3 | 45 | 0 | 28 | alto | 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: EFFIS (Copernicus), NASA FIRMS (VIIRS), ERA5 (ECMWF/Copernicus C3S) · Open-Meteo.com (CC BY 4.0). Open-Meteo.com · How we build fire pages: methodology
- Burnt area
- 494ha
- Copernicus perimeter
- Duration
- 4days
- 22 Sept 2023 – 25 Sept 2023
- Municipalities hit
- 1
- districts
- Started on
- 22 Sept
- 2023
- Heat detections
- 10
- in a single hotspot: 8 MW
- Danger at start
- 31
- High · FWI index
- Average daily power
- 18MW
- detected power per day, on average
Where it burned
HOTSPOTS BY DAY
22 Sept25 Sept
23 Sept 2023
How it evolved, day by day
22 Sept
23 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
27°high
44km/h · peak gust
33%lowest humidity
It had gone 2 days without rain (1 mm or more) when it started.
This area had burned before
No earlier perimeters overlap this fire since 2016, when the satellite record begins.
What happened to each town
-
492 ha reached on 22 Sept0.2 %
Burnt area inside each municipality, from crossing the official 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.
What burned
- Mixed forest66 %
- Other natural land19 %
- Agricultural areas13 %
- Broadleaved forest2.2 %
Land cover inside the perimeter as reported by Copernicus EFFIS (outside the Corine Land Cover area).
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) |
|---|---|---|---|---|---|
| 22 Sept | 27.0 °C | 33 % | 44 km/h | 0.2 mm | High 31 |
| 23 Sept | 27.2 °C | 52 % | 40 km/h | 0.0 mm | High 28 |
| 24 Sept | 25.8 °C | 58 % | 29 km/h | 0.0 mm | Moderate 19 |
| 25 Sept | 23.5 °C | 60 % | 34 km/h | 0.0 mm | Moderate 19 |
| 26 Sept after | 23.2 °C | 60 % | 23 km/h | 0.0 mm | Moderate 17 |
| 27 Sept after | 24.4 °C | 53 % | 20 km/h | 0.0 mm | Moderate 16 |
| 28 Sept after | 24.8 °C | 37 % | 18 km/h | 0.0 mm | Moderate 20 |
| 29 Sept after | 26.3 °C | 27 % | 19 km/h | 0.0 mm | High 27 |
| 30 Sept after | 26.1 °C | 31 % | 30 km/h | 0.0 mm | High 31 |
| 1 Oct after | 18.1 °C | 46 % | 40 km/h | 0.7 mm | High 25 |
| 2 Oct after | 17.8 °C | 44 % | 36 km/h | 0.0 mm | High 26 |
| 3 Oct after | 22.1 °C | 41 % | 36 km/h | 0.0 mm | High 28 |
| 4 Oct after | 19.0 °C | 45 % | 47 km/h | 0.5 mm | High 36 |
| 5 Oct after | 17.9 °C | 45 % | 45 km/h | 0.0 mm | High 28 |
Its twins: fires that started in the same weather
It started with an FWI of 31.3, a minimum humidity of 33% and 2 days without rain. Fires in the area that started in weather like this since 2020: 22.
FWI at the start
31.3
Minimum humidity
33 %
Days without rain
2
this fire
chosen twins
rest of the area
Almost identicalSimilar
Outlines of the closest twins
This fire · Zviahel fire, September 2023
494 ha
4 days
FWI 31.3
Min. humidity 33 %
Zviahel fire, May 2025
612 ha
4 days
FWI 29.8
Min. humidity 29 %
2 km away, in 2025
First rain (1 mm or more) after it ended: 4.0 mm on 10 May.
Ivankiv fire, August 2022
698 ha
10 days
FWI 32.3
Min. humidity 31 %
197 km away, in 2022
First rain (1 mm or more) after it ended: 12.8 mm on 10 Sept.
Poliske fire, June 2026
1,317 ha
6 days
FWI 29.3
Min. humidity 32 %
180 km away, in 2026
First rain (1 mm or more) after it ended: 3.5 mm on 4 Jul.
Kozelets fire, May 2026
240 ha
1 day
FWI 31.9
Min. humidity 35 %
226 km away, in 2026
First rain (1 mm or more) after it ended: 1.4 mm on 10 May.
Rivne fire, April 2026
210 ha
3 days
FWI 29.6
Min. humidity 28 %
67 km away, in 2026
First rain (1 mm or more) after it ended: 3.3 mm on 26 Apr.
What happened to them
- 4 days
- median duration
- 236 ha
- median area
- 18 %
- went past 1,000 ha
- 3.5 mm
- rain at the end (median; 21 of 22 had it)
It was 2.1 times larger than the median of its twins and lasted 4 days, against 4 days.
Only 8 of its 22 twins burned more. The weather on the first day does not explain everything: the wind in the following days, the fuel and the firefighting also count. In 1 of 22, not even 1 mm fell in the ten days after the end: they went out without rain. In the rest, the first rainy day brought a median of 3.5 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
—first rain
—no rain in ten days
44km/h · max. gust
It was considered over on 25 Sept, and not even 1 mm fell in the following ten days: it went out without rain. Twins with rain when they ended: 21 of 22, with a median of 3.5 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 2020.
- 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 · 15 Sept 2023
After · 2 Oct 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 28 September 2023 the air beside the fire reached 23 µg/m³ of PM2.5. That day averaged 17: 1.1 times the WHO daily guideline (15).
PM2.5 peak23 µg/m³
Days over the guideline1 day
PM1033 µg/m³
Optical depth0.37
WHO 15
20 Sept23 Sept26 Sept29 Sept2 Oct
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 · 10Every 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
- 612 haZviahel Звягель1 May 2025 · 4 days · 2 km away
- 999 haZviahel Звягель8 March 2025 · 3 days · 3 km away
- 982 haZviahel Звягель8 March 2025 · 3 days · 12 km away
- 384 haZviahel Звягель2 May 2025 · 2 days · 26 km away
- 485 haYemilchyne Ємільчинський район21 April 2025 · 3 days · 30 km away
- 621 haYemilchyne Ємільчинський район2 April 2020 · 6 days · 31 km away
Frequently asked questions
- How long did the Zviahel fire last?
- Copernicus dates it between 22 September 2023 and 25 September 2023: 4 days between the first and last image with fire.
- How much area did it burn?
- The perimeter Copernicus measured from satellite imagery is 494 hectares (4.9 km²). Official national figures may differ.
- Which municipalities burned?
- The fire only entered Zviahel (492 ha, 0.2 %).
- Did the fire reach a town?
- The fire started in Zviahel and came within 9.7 km of its centre. That is the distance from the perimeter, or the nearest hotspot, to the point marking the centre; it does not mean it entered the houses.
- What was the weather like?
- During the fire the temperature reached 27.2 °C, humidity dropped to 33 % and gusts hit 44 km/h. The fire danger index (FWI) reached 31, class High.
- Where does this data come from?
- From the EFFIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Ukraine (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 2020 with a similar FWI, humidity and dry spell: 22. Their median duration was 4 days and their median area 236 ha; 18 % went past 1,000 ha. Only 8 of its 22 twins burned more. The weather on the first day does not explain everything: the wind in the following days, the fuel and the firefighting also count. In 1 of 22, not even 1 mm fell in the ten days after the end: they went out without rain. In the rest, the first rainy day brought a median of 3.5 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: 101 · 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 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: EFFIS (Copernicus), mapped on satellite imagery.
- Dates from the perimeter: the VIIRS detections inside it did not change them. 10 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.
Where this data comes from
The perimeter and land cover come from the Copernicus European Forest Fire Information System (EFFIS), measured on MODIS and Sentinel-2 imagery and published under CC BY 4.0. 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 (Public Domain). The area per municipality is computed by WorldFires by crossing the perimeter with those boundaries, so it may differ slightly from each country’s official figure.