How long did the Fly Creek Fire last?

It burned between 28 July 2017 and 28 July 2017: 1 day, according to the start date recorded by United States agencies (MTBS / NIFC) and the heat detections seen by satellite.

How much area did it burn?

The official perimeter published by United States agencies (MTBS / NIFC) is 773 hectares (7.7 km²). Other tallies, such as daily incident reports, may give slightly different figures.

Which counties burned?

The fire only entered Big Horn (764 ha, 0.1 %).

What was the weather like?

During the fire the temperature reached 34.1 °C, humidity dropped to 16 % and gusts hit 29 km/h. The fire danger index (FWI) reached 46, 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 · 2017-07-28 → 2017-07-28

Fly Creek Fire, July 2017 Big Horn

Out · last measured on 28 Jul 2017

The fire started on 28 July 2017 in Big Horn, United States, and satellites saw it burning for 1 day. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 773 hectares, spread across a single county.

It is the 211th largest in Montana since 2016 (of 302 with a page). Number 443 in United States in 2017, of 619.

Compare with…

Suggestions: Sage Hills · 2017 Microwave · 2017 Cottonwood · 2021 Pryor Creek Rd · 2023

We have the official perimeter (MTBS / NIFC) for this fire, but the VIIRS sensors did not capture it in enough detail: no day-by-day evolution, but the split by county is there.

Burnt area: 773ha; official perimeter (MTBS / NIFC)
Duration: 1day; 28 Jul 2017 – 28 Jul 2017
Counties hit: 1; counties
Started on: 28 Jul; 2017
Danger at start: 46; Very high · FWI index

The weather it burned in

34°high

29km/h · peak gust

16%lowest humidity

It had gone 11 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.

How big is it?

It burned the equivalent of 0.5% of the area of London (7.7 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

Big Horn where it started

764 ha

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 2015

Built-up area< 0.1 ha

Residents< 20

Inside the perimeter there was no noticeable built-up land and almost nobody lived there (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)
28 Jul	34.1 °C	16 %	29 km/h	0.0 mm	Very high 46
29 Jul after	31.0 °C	23 %	34 km/h	0.0 mm	Very high 50
30 Jul after	35.5 °C	12 %	20 km/h	0.0 mm	Very high 46
31 Jul after	35.7 °C	9 %	32 km/h	0.0 mm	Extreme 57
1 Aug after	32.4 °C	15 %	34 km/h	0.4 mm	Very high 50
2 Aug after	22.9 °C	35 %	52 km/h	0.0 mm	Very high 47
3 Aug after	25.8 °C	22 %	32 km/h	0.0 mm	High 36
4 Aug after	30.4 °C	22 %	22 km/h	0.0 mm	Very high 50
5 Aug after	23.8 °C	30 %	48 km/h	0.4 mm	Very high 50
6 Aug after	24.1 °C	31 %	26 km/h	0.0 mm	High 34
7 Aug after	28.0 °C	17 %	28 km/h	0.0 mm	High 38

Before and after, from space

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

↔

Before · 21 Jul 2017

After · 4 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.

Other fires nearby

All fires in United States ›

Frequently asked questions

How long did the Fly Creek Fire last?: It burned between 28 July 2017 and 28 July 2017: 1 day, according to the start date recorded by United States agencies (MTBS / NIFC) and the heat detections seen by satellite.
How much area did it burn?: The official perimeter published by United States agencies (MTBS / NIFC) is 773 hectares (7.7 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?: The fire only entered Big Horn (764 ha, 0.1 %).
What was the weather like?: During the fire the temperature reached 34.1 °C, humidity dropped to 16 % and gusts hit 29 km/h. The fire danger index (FWI) reached 46, 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.

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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.

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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.
Dates from the perimeter: the VIIRS detections inside it did not change them. No 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