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Bear Creek Fire, August 2020 Beaverhead, Lemhi

Out · last detection 7 Sept 2020, 09:22 UTC

The fire started on 11 August 2020 in Beaverhead, United States, and satellites saw it burning for 28 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 6,062 hectares, spread across 2 counties.

It is the 49th largest in Montana since 2016 (of 302 with a page). Number 92 in United States in 2020, of 441.

Compare with…

Suggestions: Big Hollow · 2024Goldstone · 2018Hayden · 2023

Burnt area
6,062ha
official perimeter (MTBS / NIFC)
Duration
≈ 28days
11 Aug 2020 – 7 Sept 2020
Counties hit
2
counties
Started on
11 Aug
2020
Heat detections
673
in a single hotspot: 810 MW
Danger at start
33
High · FWI index
Average daily power
729MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 11 Aug7 Sept
7 Sept 2020

How it evolved, day by day

11 Aug 2020 · 1,238 MW · 47 12 Aug 2020 · 479 MW · 54 13 Aug 2020 · 444 MW · 56 14 Aug 2020 · 240 MW · 17 15 Aug 2020 · 1,108 MW · 56 16 Aug 2020 · 456 MW · 30 17 Aug 2020 · 2,316 MW · 37 18 Aug 2020 · 68 MW · 21 20 Aug 2020 · 227 MW · 5 21 Aug 2020 · 2,774 MW · 34 22 Aug 2020 · 1,514 MW · 82 23 Aug 2020 · 370 MW · 44 24 Aug 2020 · 316 MW · 36 25 Aug 2020 · 59 MW · 1 26 Aug 2020 · 33 MW · 9 28 Aug 2020 · 5 MW · 1 29 Aug 2020 · 228 MW · 10 30 Aug 2020 · 32 MW · 11 4 Sept 2020 · 15 MW · 2 5 Sept 2020 · 3,998 MW · 63 6 Sept 2020 · 91 MW · 45 7 Sept 2020 · 20 MW · 12
11 Aug 15 Aug 20 Aug 24 Aug 29 Aug 5 Sept 6 Sept

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

The weather it burned in

28°high
67km/h · peak gust
12%lowest humidity

It had gone 4 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?

10 km
It burned the equivalent of 3.8% of the area of London (61 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

  1. Beaverhead where it started
    5,989 ha reached on 11 Aug
    0.4 %
  2. Lemhi
    38 ha reached on 11 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)
11 Aug 23.7 °C 15 % 49 km/h 0.0 mm High 33
12 Aug 21.0 °C 15 % 67 km/h 0.0 mm Very high 40
13 Aug 20.1 °C 19 % 61 km/h 0.0 mm Very high 39
14 Aug 21.3 °C 19 % 32 km/h 0.0 mm High 30
15 Aug 25.1 °C 13 % 30 km/h 0.0 mm High 32
16 Aug 25.5 °C 17 % 26 km/h 0.0 mm High 31
17 Aug 28.2 °C 19 % 40 km/h 0.0 mm High 36
18 Aug 25.4 °C 24 % 35 km/h 0.6 mm High 28
19 Aug 24.2 °C 26 % 41 km/h 1.3 mm Moderate 17
20 Aug 23.6 °C 21 % 48 km/h 0.0 mm High 30
21 Aug 24.6 °C 13 % 41 km/h 0.0 mm High 36
22 Aug 25.0 °C 15 % 42 km/h 0.0 mm High 36
23 Aug 25.0 °C 18 % 40 km/h 0.4 mm High 37
24 Aug 22.4 °C 20 % 46 km/h 0.0 mm High 37
25 Aug 20.4 °C 32 % 54 km/h 1.8 mm Moderate 14
26 Aug 22.2 °C 27 % 30 km/h 0.4 mm Moderate 20
27 Aug 19.4 °C 39 % 33 km/h 0.0 mm Moderate 21
28 Aug 21.9 °C 18 % 28 km/h 0.0 mm High 26
29 Aug 23.4 °C 15 % 48 km/h 0.0 mm High 37
30 Aug 14.1 °C 19 % 46 km/h 0.0 mm High 36
31 Aug 6.3 °C 34 % 38 km/h 5.5 mm Very low 2
1 Sept 18.9 °C 33 % 48 km/h 0.0 mm Low 8
2 Sept 22.5 °C 18 % 53 km/h 0.0 mm High 25
3 Sept 23.3 °C 19 % 38 km/h 0.0 mm High 28
4 Sept 26.6 °C 13 % 22 km/h 0.0 mm High 30
5 Sept 28.4 °C 12 % 64 km/h 0.0 mm Very high 47
6 Sept 23.1 °C 18 % 36 km/h 0.0 mm High 35
7 Sept 15.6 °C 28 % 60 km/h 5.0 mm Very low 5
8 Sept after 8.7 °C 23 % 48 km/h 0.0 mm Low 8
9 Sept after 15.2 °C 24 % 27 km/h 0.0 mm Moderate 12
10 Sept after 19.3 °C 19 % 20 km/h 0.0 mm Moderate 19
11 Sept after 19.7 °C 17 % 36 km/h 0.0 mm High 25
12 Sept after 20.6 °C 15 % 30 km/h 0.0 mm High 26
13 Sept after 18.9 °C 18 % 28 km/h 0.0 mm High 26
14 Sept after 21.0 °C 16 % 38 km/h 0.0 mm High 29
15 Sept after 20.1 °C 16 % 32 km/h 0.0 mm High 28
16 Sept after 18.2 °C 16 % 28 km/h 0.0 mm High 28
17 Sept after 19.8 °C 18 % 23 km/h 0.0 mm High 27

Before and after, from space

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

Before · 4 Aug 2020
After · 14 Sept 2020

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 · 673Every 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 timeSatelliteFRP (MW)LatLon

Other fires nearby

All fires in United States ›

Frequently asked questions

How long did the Bear Creek Fire last?
The official perimeter only gives the start date (11 August 2020). The end comes from the heat detections inside the perimeter: it burned until 7 September 2020 (28 days from 11 August 2020), 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 6,062 hectares (60.6 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?
The fire entered 2 counties: Beaverhead (5,989 ha, 0.4 %); Lemhi (38 ha, 0.0 %).
What was the weather like?
During the fire the temperature reached 28.4 °C, humidity dropped to 12 % and gusts hit 67 km/h. The fire danger index (FWI) reached 47, 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

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

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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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. 673 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.