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US · United States · –

Black Rock Fire, September 2025 Wasco, Sherman, Wheeler

Out · last detection 9 Sept 2025, 21:15 UTC

The fire started on 5 September 2025 in Wasco, United States, and satellites saw it burning for 5 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 17,742 hectares, spread across 4 counties.

It is the 45th largest in Oregon since 2016 (of 325 with a page). Number 19 in United States in 2025, of 325.

The power measured by the satellite is low (28.7 MW in the strongest hotspot), more typical of grass or stubble burning, or a slow surface fire, than of a large crown fire.

Burnt area
17,742ha
official perimeter (MTBS / NIFC)
Duration
≈ 5days
5 Sept 2025 – 9 Sept 2025
Counties hit
4
counties
Started on
5 Sept
2025
Heat detections
154
in a single hotspot: 29 MW
Danger at start
45
Very high · FWI index
Average daily power
251MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 5 Sept9 Sept
9 Sept 2025

How it evolved, day by day

5 Sept 2025 · 126 MW · 33 6 Sept 2025 · 738 MW · 99 7 Sept 2025 · 75 MW · 15 9 Sept 2025 · 66 MW · 7
5 Sept 6 Sept 7 Sept 9 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

31°high
34km/h · peak gust
21%lowest humidity

It had gone more than two months without rain (1 mm or more) when it started. Rain came after the fire: 9.2 mm on 14 Sept.

This area had burned before

9% of the perimeter overlaps earlier fires recorded since 2016: 1,588 ha in 2017.

How big is it?

10 km
It burned the equivalent of 11% of the area of London (177 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 county

  1. Wasco where it started
    13,515 ha reached on 5 Sept
    2.2 %
  2. 2,133 ha reached on 6 Sept
    1.0 %
  3. 2,062 ha reached on 6 Sept
    0.5 %
  4. 16 ha
    0.0 %

Burnt area inside each county, 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.

People and buildings inside the perimeter

GHSL 2025
Built-up area0.35 ha
Residents< 20

Inside the perimeter there were about 0.35 hectares of 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)

Started with 60 days without rain: 7.0 % of the area in United States

Day High Min. humidity Peak gust Rain Danger (FWI)
5 Sept 31.4 °C 21 % 28 km/h 0.0 mm Very high 45
6 Sept 27.1 °C 35 % 22 km/h 1.5 mm High 34
7 Sept 26.6 °C 32 % 34 km/h 0.6 mm High 22
8 Sept 26.0 °C 33 % 27 km/h 1.6 mm High 26
9 Sept 22.7 °C 46 % 22 km/h 2.7 mm Low 6
10 Sept after 23.3 °C 42 % 26 km/h 0.2 mm Low 11
11 Sept after 22.8 °C 48 % 32 km/h 0.8 mm Moderate 15
12 Sept after 25.3 °C 40 % 23 km/h 0.0 mm Moderate 20
13 Sept after 28.6 °C 24 % 22 km/h 0.0 mm High 27
14 Sept after 18.6 °C 55 % 45 km/h 9.2 mm Low 6

Its twins: fires that started in the same weather

It started with an FWI of 45.2, a minimum humidity of 21% and more than two months without rain. Fires in the area that started in weather like this since 2016: 18.

FWI at the start 45.2
Minimum humidity 21 %
Days without rain 60+
this fire chosen twins rest of the area
Almost identicalSimilar

Outlines of the closest twins

Elm Fire, August 2018
694 ha 6 days FWI 43.4 Min. humidity 22 % 198 km away, in 2018

First rain (1 mm or more) after it ended: 2.3 mm on 27 Aug.

What happened to them

2 days
median duration
2,759 ha
median area
72 %
went past 1,000 ha
1.9 mm
rain at the end (median; 7 of 18 had it)

It was 6.4 times larger than the median of its twins and lasted 5 days, against 2 days.

Only 2 of its 18 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 11 of 18, 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 1.9 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

9.2 mmfirst rain
14 Sept5 days after it ended
34km/h · max. gust

It was considered over on 9 Sept, and on 14 Sept 9.2 mm fell. We do not know whether the rain or the firefighters put it out. Twins with rain when they ended: 7 of 18, with a median of 1.9 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.

How we calculate it

Before and after, from space

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

Before · 29 Aug 2025
After · 16 Sept 2025

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 7 September 2025 the air beside the fire reached 31 µg/m³ of PM2.5. That day averaged 23: 1.5 times the WHO daily guideline (15).

PM2.5 peak31 µg/m³
Days over the guideline4 days
PM1032 µg/m³
Optical depth0.91
3 Sept5 Sept7 Sept9 Sept11 Sept
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 · 154Every 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 timeSatelliteFRP (MW)LatLon

Other fires nearby

All fires in United States

Frequently asked questions

How long did the Black Rock Fire last?
The official perimeter only gives the start date (5 September 2025). The end comes from the heat detections inside the perimeter: it burned until 9 September 2025 (5 days from 5 September 2025), the last day with detections before more than 10 days in a row without any, so it is approximate.
How much area did it burn?
The official perimeter published by United States agencies (MTBS / NIFC) is 17,742 hectares (177.4 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?
The fire entered 4 counties: Wasco (13,515 ha, 2.2 %); Sherman (2,133 ha, 1.0 %); Wheeler (2,062 ha, 0.5 %); Gilliam (16 ha, 0.0 %).
What was the weather like?
During the fire the temperature reached 31.4 °C, humidity dropped to 21 % and gusts hit 34 km/h. The fire danger index (FWI) reached 45, class Very high.
Where does this data come from?
From the official burnt perimeter of United States agencies (MTBS / NIFC, public domain), NASA FIRMS VIIRS hotspots and the administrative boundaries of United States. 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: 18. Their median duration was 2 days and their median area 2,759 ha; 72 % went past 1,000 ha. Only 2 of its 18 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 11 of 18, 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 1.9 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: 911 · 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.

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
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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 911.

How we know this
  • Perimeter: NIFC WFIGS (United States), official.
  • The official perimeter has no end date: the end is the last day with VIIRS detections inside the perimeter before a gap of more than 10 days (150 days at most), so it is approximate. 154 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.

How we build fire pages: methodology

Where this data comes from

The perimeter is official and in the public domain. For past years it comes from MTBS (Monitoring Trends in Burn Severity), run by the U.S. Geological Survey and the USDA Forest Service, which map it on Landsat and Sentinel-2 imagery. For the current and last year it comes from WFIGS at the National Interagency Fire Center (NIFC): incident perimeters mapped by fire crews, aircraft and imagery. Heat detections come from the VIIRS sensors aboard Suomi-NPP and NOAA-20, distributed by NASA FIRMS at 375 m resolution. County boundaries come from geoBoundaries ADM2 (Public Domain). The area per county is computed by WorldFires by crossing the perimeter with those boundaries, so it may differ slightly from official figures.