How long did the Elk Fire last?

The official perimeter only gives the start date (27 September 2024). The end comes from the heat detections inside the perimeter: it burned until 4 October 2024 (8 days from 27 September 2024), 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 40,000 hectares (400.0 km²). Other tallies, such as daily incident reports, may give slightly different figures.

Which counties burned?

The fire only entered Sheridan (39,972 ha, 6.1 %).

What was the weather like?

During the fire the temperature reached 25.5 °C, humidity dropped to 14 % and gusts hit 47 km/h. The fire danger index (FWI) reached 23, 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 · 2024-09-27 → 2024-10-04

Elk Fire, September 2024 Sheridan

Out · last detection 4 Oct 2024, 20:46 UTC

The fire started on 27 September 2024 in Sheridan, United States, and satellites saw it burning for 8 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 40,000 hectares, spread across a single county.

It is the 4th largest in Wyoming since 2016 (of 117 with a page). Number 12 in United States in 2024, of 371.

Compare with…

Suggestions: Sheridan · 2026 Aberdeen 2 · 2017 Crater Ridge · 2021

Burnt area: 40,000ha; official perimeter (MTBS / NIFC)
Duration: ≈ 8days; 27 Sept 2024 – 4 Oct 2024
Counties hit: 1; counties
Started on: 27 Sept; 2024
Heat detections: 2,378; in a single hotspot: 532 MW
Danger at start: 19; Moderate · FWI index
Average daily power: 8.1GW; detected power per day, on average

HOTSPOTS BY DAY 27 Sept4 Oct

Play back 4 Oct 2024

How it evolved, day by day

27 Sept 29 Sept 1 Oct 2 Oct 3 Oct

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

The weather it burned in

26°high

47km/h · peak gust

14%lowest humidity

It had gone 8 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 25% of the area of London (400 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

Sheridan where it started

39,972 ha reached on 27 Sept

6.1 %

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 area2.6 ha

Residents≈ 40

Inside the perimeter there were about 2.6 hectares of built-up land and about 40 residents (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	Rain	Danger (FWI)
27 Sept	23.0 °C	21 %	28 km/h	0.0 mm	Moderate 19
28 Sept	23.1 °C	23 %	26 km/h	0.0 mm	Moderate 17
29 Sept	25.5 °C	15 %	39 km/h	0.0 mm	High 22
30 Sept	12.6 °C	20 %	47 km/h	0.0 mm	High 22
1 Oct	18.5 °C	17 %	40 km/h	0.0 mm	High 22
2 Oct	19.2 °C	18 %	41 km/h	0.0 mm	High 22
3 Oct	11.7 °C	33 %	34 km/h	0.0 mm	Moderate 15
4 Oct	21.4 °C	14 %	47 km/h	0.0 mm	High 23
5 Oct after	13.4 °C	21 %	48 km/h	0.0 mm	High 22
6 Oct after	16.2 °C	24 %	25 km/h	0.0 mm	Moderate 17
7 Oct after	17.1 °C	21 %	26 km/h	0.0 mm	Moderate 18
8 Oct after	18.7 °C	19 %	23 km/h	0.0 mm	Moderate 18
9 Oct after	20.1 °C	16 %	25 km/h	0.0 mm	Moderate 20
10 Oct after	16.3 °C	27 %	32 km/h	0.0 mm	Moderate 21
11 Oct after	17.1 °C	24 %	32 km/h	0.0 mm	Moderate 19
12 Oct after	14.5 °C	36 %	27 km/h	0.1 mm	Moderate 16
13 Oct after	13.0 °C	35 %	25 km/h	0.0 mm	Moderate 15
14 Oct after	18.3 °C	20 %	26 km/h	0.0 mm	Moderate 19

Before and after, from space

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

↔

Before · 20 Sept 2024

After · 11 Oct 2024

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 1 October 2024 the air beside the fire reached 158 µg/m³ of PM2.5. That day averaged 102: 6.8 times the WHO daily guideline (15).

PM2.5 peak158 µg/m³

Days over the guideline7 days

PM10227 µg/m³

Optical depth1.90

WHO 15

2526272829301234567

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 · 2,378Every 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 Elk Fire last?: The official perimeter only gives the start date (27 September 2024). The end comes from the heat detections inside the perimeter: it burned until 4 October 2024 (8 days from 27 September 2024), 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 40,000 hectares (400.0 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?: The fire only entered Sheridan (39,972 ha, 6.1 %).
What was the weather like?: During the fire the temperature reached 25.5 °C, humidity dropped to 14 % and gusts hit 47 km/h. The fire danger index (FWI) reached 23, 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 · 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: 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. 2,378 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