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Four Corners Fire, August 2022 Valley, Adams, Gem

Out · last detection 12 Sept 2022, 09:42 UTC

The fire started on 13 August 2022 in Valley, United States, and satellites saw it burning for 31 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 6,360 hectares, spread across 3 counties.

It is the 57th largest in Idaho since 2016 (of 379 with a page). Number 84 in United States in 2022, of 493.

Compare with…

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Burnt area
6,360ha
official perimeter (MTBS / NIFC)
Duration
≈ 31days
13 Aug 2022 – 12 Sept 2022
Counties hit
3
counties
Started on
13 Aug
2022
Heat detections
1,302
in a single hotspot: 238 MW
Danger at start
18
Moderate · FWI index
Average daily power
579MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 13 Aug12 Sept
12 Sept 2022

How it evolved, day by day

14 Aug 2022 · 315 MW · 14 15 Aug 2022 · 1,104 MW · 27 16 Aug 2022 · 2,428 MW · 117 17 Aug 2022 · 3,216 MW · 145 18 Aug 2022 · 1,060 MW · 144 19 Aug 2022 · 176 MW · 60 20 Aug 2022 · 3 MW · 3 21 Aug 2022 · 38 MW · 21 22 Aug 2022 · 136 MW · 34 23 Aug 2022 · 84 MW · 31 24 Aug 2022 · 135 MW · 33 25 Aug 2022 · 164 MW · 36 26 Aug 2022 · 2,832 MW · 102 27 Aug 2022 · 1,825 MW · 97 28 Aug 2022 · 643 MW · 84 29 Aug 2022 · 204 MW · 71 30 Aug 2022 · 212 MW · 49 31 Aug 2022 · 475 MW · 57 1 Sept 2022 · 176 MW · 66 2 Sept 2022 · 287 MW · 51 3 Sept 2022 · 39 MW · 20 4 Sept 2022 · 32 MW · 14 5 Sept 2022 · 18 MW · 5 6 Sept 2022 · 13 MW · 12 7 Sept 2022 · 13 MW · 7 9 Sept 2022 · 2 MW · 1 12 Sept 2022 · 1 MW · 1
14 Aug 17 Aug 18 Aug 22 Aug 26 Aug 30 Aug 3 Sept 7 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

29°high
53km/h · peak gust
10%lowest humidity

It had gone one day without rain (1 mm or more) when it started. Rain came after the fire: 4.9 mm on 15 Sept.

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 4% of the area of London (64 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. Valley where it started
    3,575 ha reached on 14 Aug
    0.4 %
  2. Adams
    1,673 ha reached on 14 Aug
    0.5 %
  3. Gem
    1,089 ha reached on 16 Aug
    0.8 %

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)
13 Aug 22.7 °C 23 % 33 km/h 0.0 mm Moderate 18
14 Aug 24.4 °C 14 % 31 km/h 0.0 mm High 25
15 Aug 25.5 °C 15 % 29 km/h 0.0 mm High 27
16 Aug 27.7 °C 12 % 26 km/h 0.0 mm High 31
17 Aug 28.9 °C 12 % 32 km/h 0.0 mm High 32
18 Aug 25.5 °C 20 % 33 km/h 0.0 mm High 33
19 Aug 22.8 °C 29 % 30 km/h 0.3 mm High 26
20 Aug 23.3 °C 30 % 21 km/h 0.1 mm High 24
21 Aug 25.5 °C 21 % 32 km/h 0.0 mm High 27
22 Aug 24.5 °C 24 % 37 km/h 0.5 mm High 31
23 Aug 24.5 °C 20 % 26 km/h 0.0 mm High 28
24 Aug 24.8 °C 21 % 33 km/h 0.1 mm High 31
25 Aug 23.5 °C 21 % 38 km/h 0.0 mm High 31
26 Aug 23.0 °C 23 % 39 km/h 0.0 mm High 31
27 Aug 18.4 °C 25 % 48 km/h 0.0 mm High 32
28 Aug 18.3 °C 23 % 32 km/h 0.0 mm High 28
29 Aug 23.4 °C 20 % 29 km/h 0.0 mm High 28
30 Aug 26.7 °C 15 % 26 km/h 0.0 mm High 33
31 Aug 27.6 °C 15 % 33 km/h 0.0 mm High 35
1 Sept 25.0 °C 12 % 34 km/h 0.0 mm High 36
2 Sept 26.2 °C 10 % 24 km/h 0.0 mm High 37
3 Sept 24.5 °C 17 % 43 km/h 0.0 mm Very high 39
4 Sept 24.6 °C 13 % 32 km/h 0.0 mm Very high 38
5 Sept 23.7 °C 15 % 31 km/h 0.0 mm High 38
6 Sept 27.0 °C 16 % 37 km/h 0.0 mm Very high 38
7 Sept 26.6 °C 16 % 53 km/h 0.2 mm Very high 44
8 Sept 17.9 °C 12 % 46 km/h 0.0 mm Very high 44
9 Sept 17.4 °C 15 % 32 km/h 0.0 mm High 37
10 Sept 17.8 °C 21 % 26 km/h 0.0 mm High 32
11 Sept 19.7 °C 18 % 25 km/h 0.0 mm High 32
12 Sept 17.8 °C 22 % 27 km/h 0.0 mm High 32
13 Sept after 14.5 °C 40 % 23 km/h 0.8 mm Moderate 16
14 Sept after 15.9 °C 46 % 28 km/h 0.4 mm Moderate 16
15 Sept after 13.7 °C 47 % 24 km/h 4.9 mm Very low 2

Before and after, from space

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

Before · 6 Aug 2022
After · 19 Sept 2022

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 16 August 2022 the air beside the fire reached 34 µg/m³ of PM2.5. That day averaged 18: 1.2 times the WHO daily guideline (15).

PM2.5 peak34 µg/m³
Days over the guideline1 day
PM1049 µg/m³
Optical depth0.39
111213141516
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 · 1,302Every 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 Four Corners Fire last?
The official perimeter only gives the start date (13 August 2022). The end comes from the heat detections inside the perimeter: it burned until 12 September 2022 (31 days from 13 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 6,360 hectares (63.6 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?
The fire entered 3 counties: Valley (3,575 ha, 0.4 %); Adams (1,673 ha, 0.5 %); Gem (1,089 ha, 0.8 %).
What was the weather like?
During the fire the temperature reached 28.9 °C, humidity dropped to 10 % and gusts hit 53 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

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.

Report an error
What do you think is wrong?

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. 1,302 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.