How long did the Bras fire last?

According to the heat detections seen by satellite inside the perimeter, it burned from 17 October 2026 to 18 October 2026 (2 days). The perimeter dates it from 17 October 2026 to 17 October 2026.

How much area did it burn?

The official perimeter published by United States agencies (MTBS / NIFC) is 683 hectares (6.8 km²). Other tallies, such as daily incident reports, may give slightly different figures.

Which counties burned?

The fire entered 2 counties: Lake (378 ha, 0.1 %); Sanders (302 ha, 0.0 %).

Is the Bras fire still active?

No fire detections since 18 Oct 2026, 21:14 UTC. A lack of detections is not an official extinction.

What was the weather like?

During the fire the temperature reached 21.1 °C, humidity dropped to 26 % and gusts hit 59 km/h. The fire danger index (FWI) reached 24, class 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.

US · United States · 2026-10-17 → 2026-10-18

Bras Fire, October 2026 Lake, Sanders

Out · last detection 18 Oct 2026, 21:14 UTC

The fire started on 17 October 2026 in Lake, United States, and satellites saw it burning for 2 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 683 hectares, spread across 2 counties.

It is the 228th largest in Montana since 2016 (of 302 with a page). Number 322 in United States in 2026, of 423.

The power measured by the satellite is low (26.6 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: 683ha; official perimeter (MTBS / NIFC)
Duration: 2days; 17 Oct 2026 – 18 Oct 2026
Municipalities hit: 2; counties
Started on: 17 Oct; 2026
Heat detections: 2; in a single hotspot: 27 MW
Danger at start: 24; High · FWI index
Energy released: 35MW; sum of detected power

Play back 18 Oct 2026

HOTSPOTS BY DAY 17 Oct18 Oct

How it evolved, day by day

1718

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

The weather it burned in

21°high

59km/h · peak gust

26%lowest humidity

It had gone 5 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

Lake where it started

378 ha reached on 17 Oct

0.1 %
Sanders

302 ha reached on 17 Oct

0.0 %

Burnt area inside each county, from crossing the official 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)
17 Oct	21.1 °C	26 %	59 km/h	0.0 mm	High 24
18 Oct	15.0 °C	41 %	18 km/h	0.0 mm	Moderate 13
19 Oct after	16.4 °C	41 %	14 km/h	0.1 mm	Moderate 13
20 Oct after	16.1 °C	47 %	14 km/h	0.0 mm	Moderate 11
21 Oct after	16.3 °C	44 %	13 km/h	0.0 mm	Moderate 12
22 Oct after	18.7 °C	38 %	14 km/h	0.0 mm	Moderate 12

Before and after, from space

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

↔

Before · 10 Oct 2026

After · 23 Oct 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 18 October 2026 the air beside the fire reached 18 µg/m³ of PM2.5, but no daily average passed the WHO guideline (15).

PM2.5 peak18 µg/m³

Days over the guideline0 days

PM1019 µg/m³

Optical depth0.13

WHO 15

15161718192021

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 · 2Every 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 Bras fire last?: According to the heat detections seen by satellite inside the perimeter, it burned from 17 October 2026 to 18 October 2026 (2 days). The perimeter dates it from 17 October 2026 to 17 October 2026.
How much area did it burn?: The official perimeter published by United States agencies (MTBS / NIFC) is 683 hectares (6.8 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?: The fire entered 2 counties: Lake (378 ha, 0.1 %); Sanders (302 ha, 0.0 %).
Is the Bras fire still active?: No fire detections since 18 Oct 2026, 21:14 UTC. A lack of detections is not an official extinction.
What was the weather like?: During the fire the temperature reached 21.1 °C, humidity dropped to 26 % and gusts hit 59 km/h. The fire danger index (FWI) reached 24, class 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.

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

Satellite cross-check

NASA FIRMS ↗
NIFC · Fire maps ↗

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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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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