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US · United States · –

Johnson Creek Fire, July 2021 Clearwater

Out · last detection 31 Jul 2021, 20:17 UTC

The fire started on 7 July 2021 in Clearwater, United States, and satellites saw it burning for 25 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 602 hectares, spread across a single county.

It is the 306th largest in Idaho since 2016 (of 379 with a page). Number 313 in United States in 2021, of 385.

The power measured by the satellite is low (9.4 MW in the strongest hotspot), more typical of grass or stubble burning, or a slow surface fire, than of a large crown fire.

Burnt area
602ha
official perimeter (MTBS / NIFC)
Duration
≈ 25days
7 Jul 2021 – 31 Jul 2021
Counties hit
1
counties
Started on
7 Jul
2021
Heat detections
101
in a single hotspot: 9 MW
Danger at start
52
Extreme · FWI index
Average daily power
14MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 7 Jul31 Jul
31 Jul 2021

How it evolved, day by day

9 Jul 2021 · 8 MW · 2 10 Jul 2021 · 10 MW · 4 11 Jul 2021 · 21 MW · 7 12 Jul 2021 · 28 MW · 11 13 Jul 2021 · 15 MW · 6 14 Jul 2021 · 49 MW · 8 15 Jul 2021 · 9 MW · 3 16 Jul 2021 · 6 MW · 5 17 Jul 2021 · 5 MW · 4 18 Jul 2021 · 3 MW · 3 19 Jul 2021 · 3 MW · 2 22 Jul 2021 · 4 MW · 6 23 Jul 2021 · 1 MW · 2 26 Jul 2021 · 32 MW · 12 27 Jul 2021 · 7 MW · 6 29 Jul 2021 · 9 MW · 4 30 Jul 2021 · 16 MW · 8 31 Jul 2021 · 30 MW · 8
9 Jul 14 Jul 17 Jul 23 Jul 30 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

37°high
52km/h · peak gust
7%lowest humidity

It had gone 21 days without rain (1 mm or more) when it started. Rain came after the fire: 3.1 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?

10 km
It burned the equivalent of 0.4% of the area of London (6 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. Clearwater where it started
    603 ha reached on 9 Jul
    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 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)

Started with Strong wind: 27 % of the area in United States

Day High Min. humidity Peak gust Rain Danger (FWI)
7 Jul 28.5 °C 17 % 52 km/h 0.0 mm Extreme 52
8 Jul 28.2 °C 15 % 30 km/h 0.0 mm Very high 40
9 Jul 29.7 °C 12 % 26 km/h 0.0 mm Very high 38
10 Jul 31.4 °C 9 % 37 km/h 0.0 mm Very high 44
11 Jul 30.6 °C 9 % 36 km/h 0.0 mm Very high 45
12 Jul 32.7 °C 7 % 29 km/h 0.0 mm Very high 44
13 Jul 32.5 °C 13 % 31 km/h 0.0 mm Very high 46
14 Jul 32.6 °C 11 % 31 km/h 0.0 mm Very high 48
15 Jul 29.3 °C 13 % 42 km/h 0.0 mm Very high 49
16 Jul 27.2 °C 17 % 37 km/h 0.0 mm Very high 43
17 Jul 28.2 °C 17 % 29 km/h 0.0 mm Very high 39
18 Jul 31.4 °C 15 % 30 km/h 0.0 mm Very high 41
19 Jul 29.0 °C 24 % 27 km/h 0.0 mm High 36
20 Jul 27.3 °C 25 % 32 km/h 0.0 mm High 34
21 Jul 24.4 °C 23 % 44 km/h 0.0 mm Very high 40
22 Jul 23.8 °C 14 % 35 km/h 0.0 mm High 37
23 Jul 26.1 °C 13 % 37 km/h 0.0 mm Very high 39
24 Jul 30.3 °C 11 % 28 km/h 0.0 mm Very high 41
25 Jul 31.5 °C 12 % 34 km/h 0.0 mm Very high 41
26 Jul 31.3 °C 12 % 32 km/h 0.0 mm Very high 42
27 Jul 28.5 °C 22 % 50 km/h 0.0 mm Very high 46
28 Jul 30.9 °C 23 % 30 km/h 0.2 mm Very high 39
29 Jul 33.3 °C 13 % 30 km/h 0.0 mm Very high 41
30 Jul 36.5 °C 9 % 24 km/h 0.0 mm Very high 49
31 Jul 36.8 °C 12 % 45 km/h 0.0 mm Extreme 53
1 Aug after 27.3 °C 36 % 36 km/h 3.1 mm Low 9

Its twins: fires that started in the same weather

It started with an FWI of 52.4, a minimum humidity of 17% and 21 days without rain. Fires in the area that started in weather like this since 2016: 34.

FWI at the start 52.4
Minimum humidity 17 %
Days without rain 21
this fire chosen twins rest of the area
Almost identicalSimilar

Outlines of the closest twins

Wagner Road Fire, July 2023
659 ha 1 day FWI 52.8 Min. humidity 18 % 125 km away, in 2023

First rain (1 mm or more) after it ended: none in the following ten days.

What happened to them

3 days
median duration
2,038 ha
median area
65 %
went past 1,000 ha
3.4 mm
rain at the end (median; 20 of 34 had it)

It stayed below its twins: 602 ha against a median of 2,038 ha. It lasted 25 days, against 3 days.

In 14 of 34, not even 1 mm fell in the ten days after the end: they went out without rain. In the rest, the first rainy day brought a median of 3.4 mm.

This is a bank of analogues: it shows what usually happens, not what will happen. With fewer than 15 twins we give no figures. How we calculate it

How it ended

3.1 mmfirst rain
1 Augthe day after it ended
52km/h · max. gust

It was considered over on 31 Jul, and on 1 Aug 3.1 mm fell. We do not know whether the rain or the firefighters put it out. Twins with rain when they ended: 20 of 34, with a median of 3.4 mm.

Weather on this page: Open-Meteo.com (CC BY 4.0) · Copernicus Climate Change Service (ERA5)

How a twin is chosen

  • Same area: fires that have already ended, less than 250 km from this one, since 2016.
  • Same start: we compare the FWI on the first day, the minimum humidity that day and the run of days without rain before it. The slider sets how much they may differ.
  • Only pages with final weather data (ERA5 reanalysis) calculated in the same way as this fire’s; agricultural and grass burns and pages with data under review are left out.
  • Fires burning at the same time as this one (a week before or after) are left out: they share the same spell of weather and do not count as a precedent.
  • They are sorted by similarity, and the outlines of the first five are drawn.

How we calculate it

Before and after, from space

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

Before · 30 Jun 2021
After · 7 Aug 2021

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 · 101Every 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 Johnson Creek Fire last?
The official perimeter only gives the start date (7 July 2021). The end comes from the heat detections inside the perimeter: it burned until 31 July 2021 (25 days from 7 July 2021), 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 602 hectares (6.0 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?
The fire only entered Clearwater (603 ha, 0.1 %).
What was the weather like?
During the fire the temperature reached 36.8 °C, humidity dropped to 7 % and gusts hit 52 km/h. The fire danger index (FWI) reached 53, class 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.
How did the fires that started in similar weather in this area end?
Fires less than 250 km away that started since 2016 with a similar FWI, humidity and dry spell: 34. Their median duration was 3 days and their median area 2,038 ha; 65 % went past 1,000 ha. In 14 of 34, not even 1 mm fell in the ten days after the end: they went out without rain. In the rest, the first rainy day brought a median of 3.4 mm.

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.

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
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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. 101 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.