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Twentyfive Mile Fire, August 2021 Chelan

Out · last detection 26 Sept 2021, 11:02 UTC

The fire started on 15 August 2021 in Chelan, United States, and satellites saw it burning for 43 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 9,464 hectares, spread across a single county.

It is the 44th largest in Washington since 2016 (of 285 with a page). Number 59 in United States in 2021, of 385.

Compare with…

Suggestions: Little Giant · 2026Cougar Creek · 2018Uno Peak · 2017Minnow Ridge · 2022

Burnt area
9,464ha
official perimeter (MTBS / NIFC)
Duration
≈ 43days
15 Aug 2021 – 26 Sept 2021
Counties hit
1
counties
Started on
15 Aug
2021
Heat detections
2,431
in a single hotspot: 550 MW
Danger at start
39
Very high · FWI index
Average daily power
1.3GW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 15 Aug26 Sept
26 Sept 2021

How it evolved, day by day

16 Aug 2021 · 3,205 MW · 101 17 Aug 2021 · 1,846 MW · 158 18 Aug 2021 · 2,372 MW · 90 19 Aug 2021 · 2,775 MW · 109 20 Aug 2021 · 427 MW · 119 22 Aug 2021 · 739 MW · 44 23 Aug 2021 · 236 MW · 32 24 Aug 2021 · 17 MW · 5 25 Aug 2021 · 7 MW · 6 27 Aug 2021 · 68 MW · 11 28 Aug 2021 · 308 MW · 32 29 Aug 2021 · 8,502 MW · 134 30 Aug 2021 · 1,391 MW · 117 31 Aug 2021 · 2,955 MW · 122 1 Sept 2021 · 435 MW · 71 2 Sept 2021 · 955 MW · 86 3 Sept 2021 · 732 MW · 80 4 Sept 2021 · 460 MW · 82 5 Sept 2021 · 3,105 MW · 242 6 Sept 2021 · 3,952 MW · 166 7 Sept 2021 · 2,473 MW · 161 8 Sept 2021 · 4,221 MW · 131 9 Sept 2021 · 177 MW · 68 10 Sept 2021 · 69 MW · 25 11 Sept 2021 · 13 MW · 6 12 Sept 2021 · 185 MW · 17 13 Sept 2021 · 1,064 MW · 33 14 Sept 2021 · 174 MW · 32 15 Sept 2021 · 171 MW · 30 16 Sept 2021 · 159 MW · 33 21 Sept 2021 · 8 MW · 5 23 Sept 2021 · 15 MW · 3 24 Sept 2021 · 319 MW · 28 25 Sept 2021 · 186 MW · 37 26 Sept 2021 · 47 MW · 15
16 Aug 22 Aug 28 Aug 29 Aug 2 Sept 7 Sept 12 Sept 21 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

30°high
54km/h · peak gust
22%lowest humidity

It had gone 13 days without rain (1 mm or more) when it started. Rain came after the fire: 6.0 mm on 27 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% of the area of London (95 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. Chelan where it started
    9,459 ha reached on 16 Aug
    1.2 %

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 area0.83 ha
Residents< 20

Inside the perimeter there were about 0.83 hectares of 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)
15 Aug 29.7 °C 22 % 53 km/h 0.0 mm Very high 39
16 Aug 25.1 °C 37 % 53 km/h 0.0 mm High 32
17 Aug 17.9 °C 36 % 49 km/h 0.2 mm High 28
18 Aug 24.7 °C 23 % 36 km/h 0.0 mm High 27
19 Aug 24.2 °C 32 % 34 km/h 0.0 mm High 28
20 Aug 19.5 °C 48 % 28 km/h 4.5 mm Very low 3
21 Aug 18.5 °C 61 % 33 km/h 4.5 mm Very low 0
22 Aug 17.3 °C 43 % 54 km/h 0.0 mm Very low 5
23 Aug 17.1 °C 33 % 41 km/h 0.1 mm Low 8
24 Aug 19.9 °C 34 % 28 km/h 0.0 mm Moderate 13
25 Aug 22.3 °C 25 % 31 km/h 0.0 mm Moderate 20
26 Aug 20.1 °C 42 % 47 km/h 0.0 mm Moderate 19
27 Aug 18.6 °C 39 % 35 km/h 0.0 mm Moderate 18
28 Aug 23.8 °C 30 % 29 km/h 0.0 mm Moderate 20
29 Aug 25.3 °C 24 % 32 km/h 0.0 mm High 24
30 Aug 20.6 °C 28 % 53 km/h 0.0 mm High 28
31 Aug 14.7 °C 37 % 51 km/h 0.0 mm High 23
1 Sept 18.6 °C 32 % 35 km/h 0.0 mm Moderate 20
2 Sept 21.6 °C 24 % 23 km/h 0.0 mm High 23
3 Sept 22.4 °C 25 % 28 km/h 0.0 mm High 23
4 Sept 23.5 °C 28 % 37 km/h 0.0 mm High 24
5 Sept 23.8 °C 31 % 38 km/h 0.0 mm High 26
6 Sept 24.8 °C 23 % 37 km/h 0.0 mm High 27
7 Sept 24.7 °C 28 % 25 km/h 0.0 mm High 26
8 Sept 24.0 °C 34 % 49 km/h 0.2 mm High 28
9 Sept 24.3 °C 31 % 30 km/h 0.0 mm High 26
10 Sept 16.6 °C 59 % 32 km/h 5.7 mm Very low 1
11 Sept 20.1 °C 49 % 32 km/h 1.0 mm Very low 4
12 Sept 19.5 °C 41 % 40 km/h 0.7 mm Low 8
13 Sept 20.3 °C 32 % 34 km/h 0.0 mm Moderate 14
14 Sept 20.4 °C 34 % 45 km/h 0.2 mm Moderate 18
15 Sept 15.6 °C 24 % 53 km/h 0.0 mm High 22
16 Sept 14.8 °C 25 % 39 km/h 0.0 mm Moderate 20
17 Sept 9.6 °C 38 % 42 km/h 3.0 mm Very low 3
18 Sept 12.5 °C 56 % 50 km/h 9.0 mm Very low 0
19 Sept 12.7 °C 49 % 47 km/h 0.7 mm Very low 1
20 Sept 17.3 °C 32 % 34 km/h 0.0 mm Very low 4
21 Sept 17.7 °C 36 % 27 km/h 0.0 mm Low 8
22 Sept 15.8 °C 59 % 43 km/h 0.0 mm Low 9
23 Sept 21.0 °C 29 % 35 km/h 0.0 mm Moderate 13
24 Sept 21.0 °C 31 % 24 km/h 0.0 mm Moderate 14
25 Sept 24.4 °C 27 % 32 km/h 0.0 mm Moderate 17
26 Sept 18.6 °C 37 % 52 km/h 3.6 mm Very low 2
27 Sept after 11.8 °C 61 % 39 km/h 6.0 mm Very low 0

Before and after, from space

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

Before · 8 Aug 2021
After · 3 Oct 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 · 2,431Every 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 Twentyfive Mile Fire last?
The official perimeter only gives the start date (15 August 2021). The end comes from the heat detections inside the perimeter: it burned until 26 September 2021 (43 days from 15 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 9,464 hectares (94.6 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?
The fire only entered Chelan (9,459 ha, 1.2 %).
What was the weather like?
During the fire the temperature reached 29.7 °C, humidity dropped to 22 % and gusts hit 54 km/h. The fire danger index (FWI) reached 39, 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. 2,431 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.