How long did the Bridge Coulee Fire last?

The official perimeter only gives the start date (19 July 2017). The end comes from the heat detections inside the perimeter: it burned until 26 July 2017 (15 days from 12 July 2017), 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 109,014 hectares (1,090.1 km²). Other tallies, such as daily incident reports, may give slightly different figures.

Which counties burned?

The fire entered 2 counties: Garfield (102,769 ha, 8.2 %); Petroleum (5,703 ha, 1.3 %).

What was the weather like?

During the fire the temperature reached 38.2 °C, humidity dropped to 5 % and gusts hit 53 km/h. The fire danger index (FWI) reached 77, class Very 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 · 2017-07-12 → 2017-07-26

Bridge Coulee Fire, July 2017 Garfield, Petroleum

Out · last detection 26 Jul 2017, 10:17 UTC

The fire started on 12 July 2017 in Garfield, United States, and satellites saw it burning for 15 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 109,014 hectares, spread across 2 counties.

It is the largest fire in Montana since 2016 (of 302 with a page). Number 4 in United States in 2017, of 619.

Compare with…

Suggestions: Curry · 2017 Edwards · 2017 Devils Creek · 2021 Lark · 2019

Burnt area: 109,014ha; official perimeter (MTBS / NIFC)
Duration: ≈ 15days; 12 Jul 2017 – 26 Jul 2017
Counties hit: 2; counties
Started on: 12 Jul; 2017
Heat detections: 4,911; in a single hotspot: 260 MW
Danger at start: 39; Very high · FWI index
Average daily power: 9.4GW; detected power per day, on average

HOTSPOTS BY DAY 12 Jul26 Jul

Play back 26 Jul 2017

How it evolved, day by day

12 Jul 20 Jul 22 Jul 23 Jul 24 Jul 26 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

38°high

53km/h · peak gust

5%lowest humidity

It had gone 27 days without rain (1 mm or more) when it started. Rain came after the fire: 1.5 mm on 1 Aug.

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 69% of the area of London (1,090 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

Garfield where it started

102,769 ha reached on 12 Jul

8.2 %
Petroleum

5,703 ha reached on 19 Jul

1.3 %

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 2015

Built-up area3.2 ha

Residents≈ 40

Inside the perimeter there were about 3.2 hectares of built-up land and about 40 residents (GHSL 2015, 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)
12 Jul	28.1 °C	33 %	42 km/h	0.0 mm	Very high 39
13 Jul	38.0 °C	9 %	42 km/h	0.0 mm	Extreme 65
14 Jul	36.2 °C	9 %	44 km/h	0.0 mm	Extreme 68
15 Jul	37.4 °C	11 %	53 km/h	0.0 mm	Very extreme 77
16 Jul	35.3 °C	18 %	48 km/h	2.4 mm	Very high 45
17 Jul	29.3 °C	17 %	39 km/h	0.5 mm	Very high 45
18 Jul	32.8 °C	11 %	36 km/h	0.0 mm	Extreme 52
19 Jul	35.5 °C	6 %	40 km/h	0.0 mm	Extreme 63
20 Jul	35.9 °C	6 %	37 km/h	0.0 mm	Extreme 66
21 Jul	32.2 °C	9 %	52 km/h	0.0 mm	Very extreme 72
22 Jul	31.7 °C	15 %	33 km/h	0.0 mm	Extreme 52
23 Jul	38.2 °C	5 %	32 km/h	0.0 mm	Extreme 58
24 Jul	31.1 °C	18 %	52 km/h	0.0 mm	Extreme 67
25 Jul	28.5 °C	18 %	39 km/h	0.0 mm	Extreme 57
26 Jul	34.7 °C	10 %	29 km/h	0.0 mm	Very high 50
27 Jul after	34.5 °C	13 %	42 km/h	0.0 mm	Very extreme 72
28 Jul after	36.0 °C	9 %	30 km/h	0.0 mm	Extreme 53
29 Jul after	32.8 °C	16 %	38 km/h	0.0 mm	Extreme 61
30 Jul after	38.7 °C	3 %	36 km/h	0.0 mm	Extreme 69
31 Jul after	34.8 °C	11 %	36 km/h	0.0 mm	Very extreme 78
1 Aug after	31.3 °C	17 %	46 km/h	1.5 mm	Very high 48

Before and after, from space

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

↔

Before · 5 Jul 2017

After · 2 Aug 2017

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.

Detections table · 4,911Every 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

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Frequently asked questions

How long did the Bridge Coulee Fire last?: The official perimeter only gives the start date (19 July 2017). The end comes from the heat detections inside the perimeter: it burned until 26 July 2017 (15 days from 12 July 2017), 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 109,014 hectares (1,090.1 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?: The fire entered 2 counties: Garfield (102,769 ha, 8.2 %); Petroleum (5,703 ha, 1.3 %).
What was the weather like?: During the fire the temperature reached 38.2 °C, humidity dropped to 5 % and gusts hit 53 km/h. The fire danger index (FWI) reached 77, class Very 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.

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How we know this

Perimeter: MTBS (US Geological Survey and US Forest Service), official; 3 polygons grouped in this page.
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. 4,911 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 2015, 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