How long did the Garceau Fire last?

The official perimeter only gives the start date (16 August 2022). The end comes from the heat detections inside the perimeter: it burned until 24 August 2022 (9 days from 16 August 2022), 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 2,813 hectares (28.1 km²). Other tallies, such as daily incident reports, may give slightly different figures.

Which counties burned?

The fire entered 2 counties: Lake (2,803 ha, 0.6 %); Sanders (1 ha, 0.0 %).

What was the weather like?

During the fire the temperature reached 33.6 °C, humidity dropped to 7 % and gusts hit 37 km/h. The fire danger index (FWI) reached 44, 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.

US · United States · 2022-08-16 → 2022-08-24

Garceau Fire, August 2022 Lake, Sanders

Out · last detection 24 Aug 2022, 10:37 UTC

The fire started on 16 August 2022 in Lake, United States, and satellites saw it burning for 9 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 2,813 hectares, spread across 2 counties.

It is the 86th largest in Montana since 2016 (of 302 with a page). Number 155 in United States in 2022, of 493.

Compare with…

Suggestions: Rattlesnake · 2018 Niarada · 2023 Elmo · 2022 Middle Ridge · 2023

Burnt area: 2,813ha; official perimeter (MTBS / NIFC)
Duration: ≈ 9days; 16 Aug 2022 – 24 Aug 2022
Counties hit: 2; counties
Started on: 16 Aug; 2022
Heat detections: 277; in a single hotspot: 195 MW
Danger at start: 40; Very high · FWI index
Average daily power: 1.0GW; detected power per day, on average

HOTSPOTS BY DAY 16 Aug24 Aug

Play back 24 Aug 2022

How it evolved, day by day

16 Aug 17 Aug 18 Aug 19 Aug 23 Aug 24 Aug

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

37km/h · peak gust

7%lowest humidity

It had gone 28 days without rain (1 mm or more) when it started. Rain came after the fire: 6.4 mm on 25 Aug.

This area had burned before

1% of the perimeter overlaps earlier fires recorded since 2016: 29 ha in 2018.

29 ha Rattlesnake fire, August 2018 499 ha in total; the hectares shown are those it shares with this fire

How big is it?

It burned the equivalent of 1.8% of the area of London (28 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

Lake where it started

2,803 ha reached on 16 Aug

0.6 %
Sanders

1 ha reached on 18 Aug

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 2020

Built-up area< 0.1 ha

Residents< 20

Inside the perimeter there was no noticeable built-up land and almost nobody lived there (GHSL 2020, 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.

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	Rain	Danger (FWI)
16 Aug	32.0 °C	7 %	20 km/h	0.0 mm	Very high 40
17 Aug	32.7 °C	15 %	23 km/h	0.0 mm	Very high 43
18 Aug	33.5 °C	16 %	23 km/h	0.0 mm	Very high 44
19 Aug	33.6 °C	14 %	22 km/h	0.0 mm	Very high 44
20 Aug	31.2 °C	24 %	27 km/h	0.8 mm	High 29
21 Aug	29.9 °C	28 %	22 km/h	1.1 mm	High 23
22 Aug	30.1 °C	19 %	21 km/h	0.1 mm	High 33
23 Aug	28.3 °C	22 %	31 km/h	0.3 mm	High 36
24 Aug	26.0 °C	37 %	37 km/h	1.3 mm	Moderate 19
25 Aug after	24.8 °C	44 %	28 km/h	6.4 mm	Very low 4

Before and after, from space

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

↔

Before · 9 Aug 2022

After · 31 Aug 2022

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 19 August 2022 the air beside the fire reached 212 µg/m³ of PM2.5. That day averaged 100: 6.7 times the WHO daily guideline (15).

PM2.5 peak212 µg/m³

Days over the guideline3 days

PM10303 µg/m³

Optical depth1.44

WHO 15

141516171819

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 · 277Every 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 Garceau Fire last?: The official perimeter only gives the start date (16 August 2022). The end comes from the heat detections inside the perimeter: it burned until 24 August 2022 (9 days from 16 August 2022), 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 2,813 hectares (28.1 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?: The fire entered 2 counties: Lake (2,803 ha, 0.6 %); Sanders (1 ha, 0.0 %).
What was the weather like?: During the fire the temperature reached 33.6 °C, humidity dropped to 7 % and gusts hit 37 km/h. The fire danger index (FWI) reached 44, 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.

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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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 911.

How we know this

Perimeter: MTBS (US Geological Survey and US Forest Service), 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. 277 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 2020, 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