How long did the Donka fire last?

GWIS (Copernicus) dates it between 15 March 2025 and 20 March 2025: 6 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 14,520 hectares (145.2 km²). It is an estimate: official national figures may differ.

Which municipalities burned?

The fire entered 2 municipalities: Umsning (8,048 ha, 9.7 %); Donka (6,540 ha, 2.1 %).

What was the weather like?

During the fire the temperature reached 32.7 °C, humidity dropped to 16 % and gusts hit 67 km/h. The fire danger index (FWI) reached 40, class Very high.

Where does this data come from?

From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of India (geoBoundaries). It is not an official report.

IN · India · 2025-03-15 → 2025-03-20

Donka fire, March 2025 Umsning, Donka

Out · last detection 20 Mar 2025, 19:05 UTC

The fire started on 15 March 2025 in Donka, India, and satellites saw it burning for 6 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 14,520 hectares from heat detections, spread across 2 municipalities.

It is the largest fire in Assam since 2016 (of 12 with a page). Number 11 in India in 2025, of 33.

Burnt area: 14,520ha; GWIS perimeter (Copernicus)
Duration: 6days; 15 Mar 2025 – 20 Mar 2025
Municipalities hit: 2; subdistricts
Started on: 15 Mar; 2025
Heat detections: 472; in a single hotspot: 52 MW
Danger at start: 21; Moderate · FWI index
Energy released: 3.4GW; sum of detected power

Play back 20 Mar 2025

HOTSPOTS BY DAY 15 Mar20 Mar

How it evolved, day by day

151617181920

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

The weather it burned in

33°high

67km/h · peak gust

16%lowest humidity

It had gone 11 days without rain (1 mm or more) when it started.

This area had burned before

99% of the perimeter overlaps earlier fires recorded since 2016: 7,373 ha in 2016, 10,492 ha in 2017, 6,882 ha in 2018, 9,562 ha in 2019, 7,997 ha in 2020, 7,632 ha in 2021, 11,474 ha in 2022, 6,028 ha in 2023, 8,307 ha in 2024. Part of it burned more than once, so the yearly figures add up to more than the 14,377 ha that had burned before.

What happened to each town

Umsning

8,048 ha reached on 15 Mar

9.7 %
Donka where it started

6,540 ha reached on 15 Mar

2.1 %

Burnt area inside each municipality, from crossing the GWIS perimeter with administrative boundaries. The distance is from the town centre to the nearest fire: staying a kilometre away does not mean it reached the houses.

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)
9 Mar	25.4 °C	38 %	30 km/h	0.0 mm	Moderate 21
10 Mar	28.8 °C	28 %	27 km/h	0.0 mm	High 22
11 Mar	27.8 °C	30 %	23 km/h	0.4 mm	Moderate 21
12 Mar	24.9 °C	46 %	32 km/h	5.5 mm	Very low 3
13 Mar	23.2 °C	68 %	39 km/h	1.7 mm	Very low 4
14 Mar	25.6 °C	59 %	30 km/h	0.9 mm	Very low 4
15 Mar	27.8 °C	48 %	30 km/h	0.4 mm	Low 9
16 Mar	28.0 °C	54 %	48 km/h	0.4 mm	Moderate 14
17 Mar	32.1 °C	22 %	67 km/h	0.4 mm	Very high 38
18 Mar	31.9 °C	16 %	58 km/h	0.0 mm	Very high 40
19 Mar	31.0 °C	19 %	29 km/h	0.0 mm	High 31
20 Mar	29.5 °C	32 %	32 km/h	0.0 mm	High 27
21 Mar after	25.6 °C	51 %	31 km/h	0.7 mm	Moderate 15
22 Mar after	24.2 °C	61 %	31 km/h	3.8 mm	Very low 2
23 Mar after	27.6 °C	35 %	23 km/h	0.3 mm	Low 8
24 Mar after	29.7 °C	30 %	26 km/h	0.0 mm	Moderate 18
25 Mar after	31.7 °C	22 %	21 km/h	0.0 mm	High 23
26 Mar after	32.7 °C	26 %	21 km/h	0.0 mm	High 24
27 Mar after	30.3 °C	36 %	17 km/h	0.0 mm	High 22
28 Mar after	31.6 °C	35 %	21 km/h	0.0 mm	High 22
29 Mar after	32.7 °C	33 %	36 km/h	0.1 mm	High 27
30 Mar after	33.4 °C	28 %	31 km/h	0.0 mm	High 26
31 Mar after	32.8 °C	26 %	40 km/h	0.0 mm	High 31
1 Apr after	32.9 °C	29 %	36 km/h	0.0 mm	High 29
2 Apr after	32.3 °C	35 %	32 km/h	0.0 mm	High 26
3 Apr after	33.7 °C	27 %	40 km/h	0.0 mm	High 31
4 Apr after	33.0 °C	21 %	47 km/h	0.0 mm	High 38
5 Apr after	32.6 °C	24 %	36 km/h	0.4 mm	High 36
6 Apr after	29.4 °C	40 %	28 km/h	0.0 mm	High 27

Before and after, from space

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

↔

Before · 8 Mar 2025

After · 27 Mar 2025

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.

The smoke

CAMS · Copernicus

On 21 March 2025 the air beside the fire reached 110 µg/m³ of PM2.5. That day averaged 93: 6.2 times the WHO daily guideline (15).

PM2.5 peak110 µg/m³

Days over the guideline11 days

PM10112 µg/m³

Optical depth1.83

WHO 15

1314151617181920212223

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 · 472Every 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 India ›

Frequently asked questions

How long did the Donka fire last?: GWIS (Copernicus) dates it between 15 March 2025 and 20 March 2025: 6 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 14,520 hectares (145.2 km²). It is an estimate: official national figures may differ.
Which municipalities burned?: The fire entered 2 municipalities: Umsning (8,048 ha, 9.7 %); Donka (6,540 ha, 2.1 %).
What was the weather like?: During the fire the temperature reached 32.7 °C, humidity dropped to 16 % and gusts hit 67 km/h. The fire danger index (FWI) reached 40, class Very high.
Where does this data come from?: From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of India (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

Satellite cross-check

NASA FIRMS ↗
GWIS · Copernicus ↗

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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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 ADM3 (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