How long did the Otsuchi fire last?

GWIS (Copernicus) dates it between 22 April 2026 and 26 April 2026: 5 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 1,525 hectares (15.2 km²). It is an estimate: official national figures may differ.

Which municipalities burned?

The fire only entered Otsuchi (1,467 ha, 7.3 %).

What was the weather like?

During the fire the temperature reached 20.5 °C, humidity dropped to 22 % and gusts hit 68 km/h. The fire danger index (FWI) reached 7, class Low.

Where does this data come from?

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

JP · Japan · 2026-04-22 → 2026-04-26

Otsuchi fire, 22 April 2026 大槌町 · Otsuchi

Out · last detection 26 Apr 2026, 04:30 UTC

The fire started on 22 April 2026 in Otsuchi, Japan, and satellites saw it burning for 5 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 1,525 hectares from heat detections, spread across a single municipality.

Number 4 in Japan in 2026, of 94.

Compare with…

Suggestions: Otsuchi · 2026 Kamaishi · 2017 Miyako · 2024 Ofunato · 2025

Burnt area: 1,525ha; GWIS perimeter (Copernicus)
Duration: 5days; 22 Apr 2026 – 26 Apr 2026
Municipalities hit: 1; municipalities
Started on: 22 Apr; 2026
Heat detections: 58; in a single hotspot: 36 MW
Danger at start: 7; Low · FWI index
Average daily power: 50MW; detected power per day, on average

HOTSPOTS BY DAY 22 Apr26 Apr

Play back 26 Apr 2026

How it evolved, day by day

22 Apr 24 Apr 25 Apr 26 Apr

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

The weather it burned in

20°high

68km/h · peak gust

22%lowest humidity

It had gone 0 days without rain (1 mm or more) when it started. Rain came after the fire: 5.2 mm on 27 Apr.

This area had burned before

No earlier perimeters overlap this fire since 2016, when the satellite record begins.

How big is it?

It burned the equivalent of 1% of the area of London (15 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

Otsuchi 大槌町 where it started

1,467 ha

7.3 %

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.

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 Apr	20.5 °C	22 %	68 km/h	0.0 mm	Low 7
23 Apr	15.0 °C	50 %	27 km/h	0.0 mm	Very low 4
24 Apr	14.0 °C	47 %	37 km/h	0.0 mm	Very low 4
25 Apr	11.4 °C	65 %	38 km/h	0.0 mm	Very low 4
26 Apr	16.4 °C	62 %	48 km/h	0.0 mm	Very low 5
27 Apr after	15.0 °C	80 %	41 km/h	5.2 mm	Very low 0

Before and after, from space

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

↔

Before · 15 Apr 2026

After · 3 May 2026

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 27 April 2026 the air beside the fire reached 48 µg/m³ of PM2.5. That day averaged 23: 1.5 times the WHO daily guideline (15).

PM2.5 peak48 µg/m³

Days over the guideline5 days

PM1060 µg/m³

Optical depth0.70

WHO 15

20212223242526272829

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 · 58Every 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 Japan ›

Frequently asked questions

How long did the Otsuchi fire last?: GWIS (Copernicus) dates it between 22 April 2026 and 26 April 2026: 5 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 1,525 hectares (15.2 km²). It is an estimate: official national figures may differ.
Which municipalities burned?: The fire only entered Otsuchi (1,467 ha, 7.3 %).
What was the weather like?: During the fire the temperature reached 20.5 °C, humidity dropped to 22 % and gusts hit 68 km/h. The fire danger index (FWI) reached 7, class Low.
Where does this data come from?: From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Japan (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: 119 · Emergency number and official warnings ›

Satellite cross-check

NASA FIRMS ↗
GWIS · Copernicus ↗

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

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 do you think is wrong?

Dates or duration Place or towns Burned area Name It was not a wildfire Same fire as another page Something else

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 119.

How we know this

Perimeter: GWIS (Copernicus), rebuilt from heat detections rather than mapped on imagery.
Dates from the perimeter: the VIIRS detections inside it did not change them. 58 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.

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 (Creative Commons Attribution-ShareAlike 2.0). 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