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Little Mud River Fire, June 2019 Yukon-Koyukuk

Out · last detection 1 Aug 2019, 21:51 UTC

The fire started on 21 June 2019 in Yukon-Koyukuk, United States, and satellites saw it burning for 42 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 39,724 hectares, spread across a single county.

It is the 18th largest in Alaska since 2016 (of 472 with a page). Number 10 in United States in 2019, of 367.

Compare with…

Suggestions: Chitanana · 2022Bear Creek · 2025Big Mud · 2016

Burnt area
39,724ha
official perimeter (MTBS / NIFC)
Duration
≈ 42days
21 Jun 2019 – 1 Aug 2019
Counties hit
1
counties
Started on
21 Jun
2019
Heat detections
3,578
in a single hotspot: 348 MW
Danger at start
2
Very low · FWI index
Average daily power
1.7GW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 21 Jun1 Aug
1 Aug 2019

How it evolved, day by day

22 Jun 2019 · 12 MW · 3 23 Jun 2019 · 9 MW · 2 24 Jun 2019 · 4 MW · 1 29 Jun 2019 · 75 MW · 12 7 Jul 2019 · 12 MW · 3 8 Jul 2019 · 10,563 MW · 308 9 Jul 2019 · 8,581 MW · 764 10 Jul 2019 · 3,156 MW · 478 11 Jul 2019 · 10,180 MW · 568 12 Jul 2019 · 117 MW · 22 13 Jul 2019 · 26 MW · 3 14 Jul 2019 · 47 MW · 3 16 Jul 2019 · 44 MW · 11 17 Jul 2019 · 6 MW · 1 20 Jul 2019 · 2 MW · 1 21 Jul 2019 · 117 MW · 12 22 Jul 2019 · 474 MW · 57 23 Jul 2019 · 1,102 MW · 212 24 Jul 2019 · 834 MW · 251 25 Jul 2019 · 259 MW · 17 27 Jul 2019 · 7 MW · 1 29 Jul 2019 · 2,482 MW · 137 30 Jul 2019 · 3,211 MW · 462 31 Jul 2019 · 2,295 MW · 245 1 Aug 2019 · 32 MW · 4
22 Jun 8 Jul 13 Jul 21 Jul 27 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

31°high
48km/h · peak gust
25%lowest humidity

It had gone 0 days without rain (1 mm or more) when it started. Rain came after the fire: 22.4 mm on 2 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 25% of the area of London (397 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. Yukon-Koyukuk where it started
    39,047 ha reached on 22 Jun
    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)

Day High Min. humidity Peak gust Rain Danger (FWI)
21 Jun 26.8 °C 36 % 22 km/h 2.2 mm Very low 2
22 Jun 25.6 °C 31 % 24 km/h 0.0 mm Very low 4
23 Jun 21.9 °C 44 % 31 km/h 0.0 mm Low 9
24 Jun 22.5 °C 39 % 30 km/h 0.0 mm Moderate 14
25 Jun 23.5 °C 32 % 19 km/h 0.0 mm Moderate 14
26 Jun 25.8 °C 31 % 19 km/h 0.0 mm Moderate 15
27 Jun 25.3 °C 43 % 21 km/h 0.0 mm Moderate 15
28 Jun 30.7 °C 31 % 23 km/h 0.0 mm Moderate 15
29 Jun 27.6 °C 40 % 35 km/h 0.0 mm High 23
30 Jun 21.0 °C 47 % 44 km/h 0.5 mm Moderate 19
1 Jul 19.5 °C 38 % 36 km/h 0.0 mm Moderate 16
2 Jul 19.7 °C 54 % 23 km/h 0.0 mm Moderate 15
3 Jul 16.3 °C 73 % 30 km/h 2.8 mm Very low 1
4 Jul 19.5 °C 57 % 23 km/h 0.0 mm Very low 4
5 Jul 27.2 °C 37 % 24 km/h 0.0 mm Low 9
6 Jul 27.7 °C 37 % 22 km/h 0.0 mm Moderate 15
7 Jul 29.0 °C 32 % 27 km/h 0.0 mm High 23
8 Jul 29.3 °C 31 % 30 km/h 0.0 mm High 28
9 Jul 29.9 °C 25 % 30 km/h 0.0 mm High 31
10 Jul 28.7 °C 33 % 30 km/h 0.1 mm High 31
11 Jul 27.6 °C 37 % 38 km/h 1.3 mm High 32
12 Jul 19.6 °C 78 % 28 km/h 19.1 mm Very low 0
13 Jul 23.6 °C 49 % 28 km/h 1.7 mm Very low 0
14 Jul 23.7 °C 45 % 28 km/h 1.4 mm Very low 2
15 Jul 25.0 °C 39 % 18 km/h 1.8 mm Very low 4
16 Jul 23.6 °C 47 % 23 km/h 2.3 mm Very low 3
17 Jul 22.6 °C 67 % 23 km/h 5.3 mm Very low 1
18 Jul 22.1 °C 47 % 38 km/h 0.0 mm Very low 2
19 Jul 19.3 °C 54 % 31 km/h 0.0 mm Very low 4
20 Jul 18.2 °C 59 % 44 km/h 0.3 mm Low 8
21 Jul 21.7 °C 49 % 40 km/h 0.0 mm Low 10
22 Jul 23.5 °C 47 % 19 km/h 0.0 mm Low 7
23 Jul 26.8 °C 40 % 18 km/h 0.0 mm Moderate 11
24 Jul 21.8 °C 61 % 39 km/h 11.9 mm Low 7
25 Jul 20.4 °C 43 % 34 km/h 0.0 mm Very low 1
26 Jul 15.8 °C 63 % 31 km/h 1.1 mm Very low 2
27 Jul 18.7 °C 50 % 18 km/h 1.0 mm Very low 4
28 Jul 19.2 °C 49 % 24 km/h 3.4 mm Very low 0
29 Jul 20.8 °C 45 % 31 km/h 0.0 mm Very low 3
30 Jul 20.8 °C 44 % 35 km/h 0.0 mm Low 9
31 Jul 21.0 °C 43 % 48 km/h 3.7 mm Moderate 14
1 Aug 17.1 °C 44 % 41 km/h 1.4 mm Very low 2
2 Aug after 18.6 °C 65 % 72 km/h 22.4 mm Very low 0

Its twins: fires that started in the same weather

It started with an FWI of 1.8, a minimum humidity of 36% and rain the day before. Fires in the area that started in weather like this since 2016: 28.

FWI at the start 1.8
Minimum humidity 36 %
Days without rain 0
this fire chosen twins rest of the area
Almost identicalSimilar

Outlines of the closest twins

Chitanana Fire, June 2022
42,768 ha 26 days FWI 0.2 Min. humidity 36 % 78 km away, in 2022

First rain (1 mm or more) after it ended: 2.7 mm on 16 Jul.

See its page Compare with this fire

What happened to them

14 days
median duration
4,827 ha
median area
39 %
went past 10,000 ha
6.0 mm
rain at the end (median; 28 of 28 had it)

It was 8.2 times larger than the median of its twins and lasted 42 days, against 14 days.

Only 1 of its 28 twins burned more. The weather on the first day does not explain everything: the wind in the following days, the fuel and the firefighting also count. All of them had rain in the ten days after the end: the first rainy day brought a median of 6.0 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

22.4 mmfirst rain
2 Augthe day after it ended
48km/h · max. gust

It was considered over on 1 Aug, and on 2 Aug 22.4 mm fell. We do not know whether the rain or the firefighters put it out. Twins with rain when they ended: 28 of 28, with a median of 6.0 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 · 14 Jun 2019
After · 8 Aug 2019

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 · 3,578Every 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 Little Mud River Fire last?
The official perimeter only gives the start date (21 June 2019). The end comes from the heat detections inside the perimeter: it burned until 1 August 2019 (42 days from 21 June 2019), 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 39,724 hectares (397.2 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?
The fire only entered Yukon-Koyukuk (39,047 ha, 0.1 %).
What was the weather like?
During the fire the temperature reached 30.7 °C, humidity dropped to 25 % and gusts hit 48 km/h. The fire danger index (FWI) reached 32, class 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.
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: 28. Their median duration was 14 days and their median area 4,827 ha; 39 % went past 10,000 ha. Only 1 of its 28 twins burned more. The weather on the first day does not explain everything: the wind in the following days, the fuel and the firefighting also count. All of them had rain in the ten days after the end: the first rainy day brought a median of 6.0 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.

No changes since 24 October 2026.

RSS Changes to this page With cross-checks and a citable version

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. 3,578 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.