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Walker Creek Fire, August 2021 Okanogan

Out · last detection 10 Sept 2021, 11:02 UTC

The fire started on 3 August 2021 in Okanogan, United States, and satellites saw it burning for 39 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 10,586 hectares, spread across a single county.

It is the 37th largest in Washington since 2016 (of 285 with a page). Number 53 in United States in 2021, of 385.

Compare with…

Suggestions: Anglin · 2020Green · 2020Customs Road · 2020Eagle Bluff · 2023

Burnt area
10,586ha
official perimeter (MTBS / NIFC)
Duration
≈ 39days
3 Aug 2021 – 10 Sept 2021
Counties hit
1
counties
Started on
3 Aug
2021
Heat detections
2,327
in a single hotspot: 508 MW
Danger at start
30
High · FWI index
Average daily power
2.0GW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 3 Aug10 Sept
10 Sept 2021

How it evolved, day by day

5 Aug 2021 · 531 MW · 19 6 Aug 2021 · 4,711 MW · 194 9 Aug 2021 · 87 MW · 20 10 Aug 2021 · 195 MW · 28 11 Aug 2021 · 6,027 MW · 151 12 Aug 2021 · 13,414 MW · 373 13 Aug 2021 · 10,578 MW · 650 14 Aug 2021 · 1,893 MW · 214 15 Aug 2021 · 4,604 MW · 321 16 Aug 2021 · 1,359 MW · 119 17 Aug 2021 · 500 MW · 78 18 Aug 2021 · 160 MW · 9 19 Aug 2021 · 371 MW · 45 20 Aug 2021 · 66 MW · 30 23 Aug 2021 · 1 MW · 1 29 Aug 2021 · 5 MW · 1 3 Sept 2021 · 2 MW · 2 4 Sept 2021 · 9 MW · 1 5 Sept 2021 · 2 MW · 3 7 Sept 2021 · 35 MW · 6 8 Sept 2021 · 1,130 MW · 33 9 Sept 2021 · 110 MW · 16 10 Sept 2021 · 87 MW · 13
5 Aug 11 Aug 12 Aug 15 Aug 19 Aug 3 Sept 8 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

32°high
62km/h · peak gust
15%lowest humidity

It had gone one day without rain (1 mm or more) when it started. Rain came after the fire: 1.3 mm on 11 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 6.7% of the area of London (106 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. Okanogan where it started
    10,629 ha reached on 5 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 area1.6 ha
Residents≈ 50

Inside the perimeter there were about 1.6 hectares of built-up land and about 50 residents (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)
3 Aug 30.1 °C 20 % 40 km/h 0.0 mm High 30
4 Aug 29.1 °C 20 % 31 km/h 0.8 mm High 30
5 Aug 28.9 °C 19 % 44 km/h 0.2 mm High 36
6 Aug 26.4 °C 27 % 47 km/h 0.2 mm High 38
7 Aug 22.1 °C 40 % 38 km/h 0.6 mm High 28
8 Aug 15.0 °C 54 % 47 km/h 9.0 mm Very low 1
9 Aug 23.5 °C 35 % 32 km/h 0.0 mm Low 6
10 Aug 27.0 °C 29 % 48 km/h 0.0 mm High 23
11 Aug 31.6 °C 22 % 45 km/h 0.0 mm High 31
12 Aug 29.9 °C 18 % 46 km/h 0.0 mm High 35
13 Aug 30.1 °C 15 % 26 km/h 0.0 mm High 32
14 Aug 31.2 °C 19 % 34 km/h 0.0 mm High 35
15 Aug 30.2 °C 16 % 45 km/h 0.0 mm Very high 40
16 Aug 25.9 °C 28 % 42 km/h 0.7 mm High 30
17 Aug 16.9 °C 47 % 62 km/h 5.1 mm Very low 5
18 Aug 23.7 °C 23 % 31 km/h 0.0 mm Moderate 12
19 Aug 22.2 °C 37 % 41 km/h 0.2 mm Moderate 18
20 Aug 20.0 °C 36 % 25 km/h 6.4 mm Very low 2
21 Aug 17.1 °C 60 % 23 km/h 9.9 mm Very low 0
22 Aug 19.2 °C 31 % 46 km/h 0.8 mm Very low 3
23 Aug 15.6 °C 33 % 35 km/h 0.0 mm Low 7
24 Aug 19.7 °C 30 % 22 km/h 0.0 mm Low 10
25 Aug 22.0 °C 26 % 27 km/h 0.0 mm Moderate 14
26 Aug 20.9 °C 30 % 35 km/h 0.0 mm Moderate 16
27 Aug 17.1 °C 45 % 40 km/h 0.7 mm Low 11
28 Aug 21.8 °C 33 % 31 km/h 0.0 mm Moderate 13
29 Aug 24.0 °C 26 % 35 km/h 0.0 mm Moderate 18
30 Aug 22.5 °C 21 % 41 km/h 0.0 mm High 22
31 Aug 14.6 °C 36 % 36 km/h 1.1 mm Low 9
1 Sept 15.7 °C 39 % 38 km/h 0.0 mm Moderate 12
2 Sept 18.6 °C 29 % 36 km/h 0.0 mm Moderate 16
3 Sept 21.6 °C 25 % 31 km/h 0.0 mm Moderate 18
4 Sept 22.1 °C 24 % 42 km/h 0.0 mm High 23
5 Sept 22.7 °C 32 % 28 km/h 0.0 mm Moderate 20
6 Sept 23.5 °C 25 % 30 km/h 0.0 mm High 22
7 Sept 25.8 °C 22 % 21 km/h 0.0 mm High 22
8 Sept 24.6 °C 28 % 49 km/h 0.4 mm High 29
9 Sept 24.6 °C 26 % 34 km/h 0.0 mm High 26
10 Sept 18.5 °C 45 % 20 km/h 6.5 mm Very low 1
11 Sept after 19.4 °C 47 % 32 km/h 1.3 mm Very low 3

Before and after, from space

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

Before · 27 Jul 2021
After · 17 Sept 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 · 2,327Every 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 Walker Creek Fire last?
The official perimeter only gives the start date (3 August 2021). The end comes from the heat detections inside the perimeter: it burned until 10 September 2021 (39 days from 3 August 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 10,586 hectares (105.9 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?
The fire only entered Okanogan (10,629 ha, 0.8 %).
What was the weather like?
During the fire the temperature reached 31.6 °C, humidity dropped to 15 % and gusts hit 62 km/h. The fire danger index (FWI) reached 40, 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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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. 2,327 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.