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Swan Lake Fire, June 2019 Kenai Peninsula

Out · last detection 23 Jul 2019, 13:05 UTC

The fire started on 6 June 2019 in Kenai Peninsula, United States, and satellites saw it burning for 48 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 66,676 hectares, spread across a single county.

It is the 9th largest in Alaska since 2016 (of 472 with a page). Number 4 in United States in 2019, of 367.

Compare with…

Suggestions: East Fork · 2017Telaquana River · 2022

Burnt area
66,676ha
official perimeter (MTBS / NIFC)
Duration
≈ 48days
6 Jun 2019 – 23 Jul 2019
Counties hit
1
counties
Started on
6 Jun
2019
Heat detections
3,750
in a single hotspot: 251 MW
Danger at start
1
Very low · FWI index
Average daily power
1.2GW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 6 Jun23 Jul
23 Jul 2019

How it evolved, day by day

6 Jun 2019 · 5 MW · 3 9 Jun 2019 · 100 MW · 3 10 Jun 2019 · 1,022 MW · 32 11 Jun 2019 · 260 MW · 36 12 Jun 2019 · 73 MW · 47 13 Jun 2019 · 878 MW · 38 14 Jun 2019 · 2,354 MW · 88 17 Jun 2019 · 2 MW · 1 18 Jun 2019 · 94 MW · 11 19 Jun 2019 · 6,016 MW · 138 20 Jun 2019 · 615 MW · 28 21 Jun 2019 · 117 MW · 28 22 Jun 2019 · 750 MW · 38 23 Jun 2019 · 1,659 MW · 129 24 Jun 2019 · 1,961 MW · 324 25 Jun 2019 · 1,590 MW · 146 26 Jun 2019 · 5,297 MW · 218 27 Jun 2019 · 4,321 MW · 379 28 Jun 2019 · 2,520 MW · 368 29 Jun 2019 · 2,861 MW · 308 30 Jun 2019 · 3,594 MW · 286 1 Jul 2019 · 1,978 MW · 91 2 Jul 2019 · 41 MW · 38 3 Jul 2019 · 335 MW · 64 4 Jul 2019 · 3,132 MW · 246 5 Jul 2019 · 1,408 MW · 180 6 Jul 2019 · 1,011 MW · 104 7 Jul 2019 · 690 MW · 69 8 Jul 2019 · 625 MW · 128 9 Jul 2019 · 279 MW · 95 10 Jul 2019 · 102 MW · 41 11 Jul 2019 · 1 MW · 1 13 Jul 2019 · 8 MW · 4 17 Jul 2019 · 22 MW · 5 18 Jul 2019 · 60 MW · 20 19 Jul 2019 · 45 MW · 7 22 Jul 2019 · 25 MW · 4 23 Jul 2019 · 5 MW · 4
6 Jun 19 Jun 26 Jun 4 Jul 13 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

29°high
53km/h · peak gust
33%lowest humidity

It had gone one day without rain (1 mm or more) when it started. Rain came after the fire: 4.3 mm on 24 Jul.

This area had burned before

0% of the perimeter overlaps earlier fires recorded since 2016: 62 ha in 2017.

How big is it?

10 km
It burned the equivalent of 42% of the area of London (667 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. Kenai Peninsula where it started
    67,551 ha reached on 6 Jun
    1.6 %

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)
6 Jun 17.4 °C 57 % 29 km/h 2.3 mm Very low 1
7 Jun 18.6 °C 54 % 21 km/h 13.5 mm Very low 0
8 Jun 15.9 °C 58 % 24 km/h 6.8 mm Very low 0
9 Jun 14.5 °C 60 % 26 km/h 0.0 mm Very low 0
10 Jun 20.1 °C 43 % 25 km/h 3.8 mm Very low 0
11 Jun 19.2 °C 48 % 28 km/h 2.2 mm Very low 0
12 Jun 16.5 °C 49 % 18 km/h 0.2 mm Very low 0
13 Jun 17.9 °C 54 % 16 km/h 0.2 mm Very low 1
14 Jun 14.8 °C 56 % 35 km/h 0.0 mm Very low 3
15 Jun 12.8 °C 63 % 35 km/h 2.6 mm Very low 2
16 Jun 14.7 °C 58 % 37 km/h 0.0 mm Very low 1
17 Jun 16.2 °C 54 % 32 km/h 0.1 mm Very low 4
18 Jun 13.2 °C 69 % 26 km/h 1.3 mm Very low 1
19 Jun 17.9 °C 51 % 29 km/h 0.0 mm Very low 3
20 Jun 18.6 °C 52 % 20 km/h 0.2 mm Very low 4
21 Jun 19.6 °C 39 % 28 km/h 0.0 mm Low 7
22 Jun 18.4 °C 48 % 29 km/h 0.0 mm Low 8
23 Jun 24.1 °C 51 % 35 km/h 3.0 mm Low 9
24 Jun 21.1 °C 57 % 26 km/h 3.8 mm Very low 1
25 Jun 18.4 °C 55 % 30 km/h 0.5 mm Very low 1
26 Jun 21.0 °C 50 % 26 km/h 0.0 mm Very low 2
27 Jun 24.8 °C 44 % 23 km/h 0.0 mm Low 6
28 Jun 25.4 °C 40 % 25 km/h 0.0 mm Low 10
29 Jun 26.2 °C 39 % 27 km/h 0.0 mm Moderate 13
30 Jun 23.1 °C 46 % 38 km/h 0.0 mm Moderate 14
1 Jul 21.1 °C 49 % 33 km/h 0.0 mm Moderate 15
2 Jul 22.8 °C 41 % 28 km/h 0.0 mm Moderate 14
3 Jul 25.4 °C 37 % 29 km/h 0.0 mm Moderate 16
4 Jul 28.7 °C 37 % 35 km/h 0.0 mm Moderate 18
5 Jul 26.2 °C 40 % 31 km/h 0.0 mm Moderate 17
6 Jul 26.8 °C 37 % 30 km/h 0.0 mm Moderate 18
7 Jul 28.1 °C 33 % 32 km/h 0.0 mm Moderate 20
8 Jul 28.1 °C 36 % 23 km/h 0.2 mm Moderate 20
9 Jul 23.8 °C 50 % 23 km/h 4.0 mm Moderate 17
10 Jul 18.6 °C 64 % 26 km/h 0.7 mm Very low 2
11 Jul 18.5 °C 67 % 26 km/h 4.0 mm Very low 3
12 Jul 18.9 °C 62 % 19 km/h 1.6 mm Very low 1
13 Jul 17.9 °C 59 % 24 km/h 0.0 mm Very low 2
14 Jul 15.6 °C 66 % 34 km/h 0.8 mm Very low 4
15 Jul 17.0 °C 60 % 53 km/h 3.6 mm Very low 3
16 Jul 17.4 °C 68 % 41 km/h 6.8 mm Very low 0
17 Jul 19.7 °C 55 % 37 km/h 0.2 mm Very low 1
18 Jul 22.3 °C 50 % 24 km/h 0.7 mm Very low 3
19 Jul 22.0 °C 54 % 27 km/h 9.7 mm Very low 5
20 Jul 17.7 °C 71 % 24 km/h 2.3 mm Very low 0
21 Jul 20.6 °C 60 % 26 km/h 0.0 mm Very low 1
22 Jul 22.3 °C 55 % 24 km/h 8.7 mm Very low 2
23 Jul 19.4 °C 63 % 19 km/h 16.8 mm Very low 0
24 Jul after 16.8 °C 65 % 22 km/h 4.3 mm Very low 0

Its twins: fires that started in the same weather

It started with an FWI of 0.7, a minimum humidity of 57% and 1 day without rain. Fires in the area that started in weather like this since 2017: 2.

FWI at the start 0.7
Minimum humidity 57 %
Days without rain 1
this fire chosen twins rest of the area
Almost identicalSimilar

Outlines of the closest twins

East Fork Fire, June 2017
447 ha 3 days FWI 4.6 Min. humidity 48 % 19 km away, in 2017

First rain (1 mm or more) after it ended: 2.5 mm on 19 Jun.

What happened to them

Fires in the area that started in similar weather: 2. With fewer than 15 we give no figures: they would be more noise than signal.

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

4.3 mmfirst rain
24 Julthe day after it ended
53km/h · max. gust

It was considered over on 23 Jul, and on 24 Jul 4.3 mm fell. We do not know whether the rain or the firefighters put it out.

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 2017.
  • 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 May 2019
After · 30 Jul 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 · 3,750Every 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 Swan Lake Fire last?
The official perimeter only gives the start date (6 June 2019). The end comes from the heat detections inside the perimeter: it burned until 23 July 2019 (48 days from 6 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 66,676 hectares (666.8 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?
The fire only entered Kenai Peninsula (67,551 ha, 1.6 %).
What was the weather like?
During the fire the temperature reached 28.7 °C, humidity dropped to 33 % and gusts hit 53 km/h. The fire danger index (FWI) reached 20, class Moderate.
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.

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. 3,750 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.