How long did the Bald Mountain Fire last?

The official perimeter only gives the start date (23 July 2026). The end comes from the heat detections inside the perimeter: it burned until 30 July 2026 (8 days from 23 July 2026), 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 30,935 hectares (309.4 km²). Other tallies, such as daily incident reports, may give slightly different figures.

Which counties burned?

The fire entered 2 counties: Harney (29,790 ha, 1.1 %); Malheur (2,044 ha, 0.1 %).

What was the weather like?

During the fire the temperature reached 33.7 °C, humidity dropped to 4 % and gusts hit 53 km/h. The fire danger index (FWI) reached 68, class Extreme.

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.

US · United States · 2026-07-23 → 2026-07-30

Bald Mountain Fire, July 2026 Harney, Malheur

Out · last detection 30 Jul 2026, 21:50 UTC

The fire started on 23 July 2026 in Harney, United States, and satellites saw it burning for 8 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 30,935 hectares, spread across 2 counties.

It is the 25th largest in Oregon since 2016 (of 327 with a page). Number 17 in United States in 2026, of 423.

Compare with…

Suggestions: Neals Hill · 2020 Porcupine · 2024 Wildcat · 2020 Jackass Butte · 2026

Burnt area: 30,935ha; official perimeter (MTBS / NIFC)
Duration: ≈ 8days; 23 Jul 2026 – 30 Jul 2026
Counties hit: 2; counties
Started on: 23 Jul; 2026
Heat detections: 1,367; in a single hotspot: 158 MW
Danger at start: 34; High · FWI index
Average daily power: 2.9GW; detected power per day, on average

HOTSPOTS BY DAY 23 Jul30 Jul

Play back 30 Jul 2026

How it evolved, day by day

24 Jul 25 Jul 26 Jul 27 Jul 28 Jul 29 Jul 30 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

34°high

53km/h · peak gust

4%lowest humidity

It had gone 0 days without rain (1 mm or more) when it started.

This area had burned before

4% of the perimeter overlaps earlier fires recorded since 2016: 1,355 ha in 2020.

1,355 ha Neals Hill fire, August 2020 1,381 ha in total; the hectares shown are those it shares with this fire

How big is it?

It burned the equivalent of 20% of the area of London (309 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

Harney where it started

29,790 ha reached on 24 Jul

1.1 %
Malheur

2,044 ha reached on 26 Jul

0.1 %

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 area0.65 ha

Residents< 20

Inside the perimeter there were about 0.65 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)

Day	High	Min. humidity	Peak gust	Danger (FWI)
23 Jul	30.8 °C	19 %	28 km/h	High 34
24 Jul	33.7 °C	4 %	40 km/h	Extreme 57
25 Jul	31.8 °C	5 %	53 km/h	Extreme 68
26 Jul	29.7 °C	9 %	38 km/h	Extreme 55
27 Jul	29.4 °C	9 %	33 km/h	Extreme 51
28 Jul	29.7 °C	12 %	38 km/h	Extreme 53
29 Jul	30.5 °C	14 %	34 km/h	Extreme 51
30 Jul	31.1 °C	11 %	30 km/h	Very high 49
31 Jul after	33.5 °C	9 %	37 km/h	Extreme 51
1 Aug after	32.0 °C	12 %	46 km/h	Extreme 60
2 Aug after	25.6 °C	10 %	41 km/h	Extreme 58
3 Aug after	23.9 °C	11 %	30 km/h	Very high 47
4 Aug after	28.9 °C	7 %	29 km/h	Very high 47
5 Aug after	33.5 °C	5 %	31 km/h	Extreme 51
6 Aug after	34.3 °C	2 %	28 km/h	Extreme 58
7 Aug after	34.3 °C	7 %	38 km/h	Extreme 60
8 Aug after	33.3 °C	8 %	45 km/h	Extreme 67
9 Aug after	31.8 °C	9 %	40 km/h	Extreme 63

Before and after, from space

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

↔

Before · 16 Jul 2026

After · 6 Aug 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 July 2026 the air beside the fire reached 207 µg/m³ of PM2.5. That day averaged 97: 6.5 times the WHO daily guideline (15).

PM2.5 peak207 µg/m³

Days over the guideline10 days

PM10210 µg/m³

Optical depth1.16

WHO 15

212223242526272829303112

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 · 1,367Every 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 United States ›

Frequently asked questions

How long did the Bald Mountain Fire last?: The official perimeter only gives the start date (23 July 2026). The end comes from the heat detections inside the perimeter: it burned until 30 July 2026 (8 days from 23 July 2026), 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 30,935 hectares (309.4 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?: The fire entered 2 counties: Harney (29,790 ha, 1.1 %); Malheur (2,044 ha, 0.1 %).
What was the weather like?: During the fire the temperature reached 33.7 °C, humidity dropped to 4 % and gusts hit 53 km/h. The fire danger index (FWI) reached 68, class Extreme.
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.

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

NASA FIRMS ↗
NIFC · Fire maps ↗

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

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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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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. 1,367 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.

Where it burned