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US · United States · –

Sischu Fire, July 2022 Yukon-Koyukuk

Out · last detection 12 Jul 2022, 23:57 UTC

The fire started on 7 July 2022 in Yukon-Koyukuk, United States, and satellites saw it burning for 6 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 3,487 hectares, spread across a single county.

It is the 194th largest in Alaska since 2016 (of 472 with a page). Number 133 in United States in 2022, of 493.

Burnt area
3,487ha
official perimeter (MTBS / NIFC)
Duration
≈ 6days
7 Jul 2022 – 12 Jul 2022
Counties hit
1
counties
Started on
7 Jul
2022
Heat detections
188
in a single hotspot: 97 MW
Danger at start
5
Very low · FWI index
Average daily power
374MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 7 Jul12 Jul
12 Jul 2022

How it evolved, day by day

7 Jul 2022 · 9 MW · 5 8 Jul 2022 · 16 MW · 3 9 Jul 2022 · 978 MW · 35 11 Jul 2022 · 186 MW · 19 12 Jul 2022 · 684 MW · 126
7 Jul 8 Jul 9 Jul 11 Jul 12 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

26°high
34km/h · peak gust
33%lowest humidity

It had gone 0 days without rain (1 mm or more) when it started. Rain came after the fire: 18.3 mm on 15 Jul.

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 2.2% of the area of London (35 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
    3,332 ha reached on 7 Jul
    0.0 %

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)
7 Jul 19.7 °C 51 % 17 km/h 0.5 mm Very low 5
8 Jul 24.4 °C 36 % 21 km/h 0.2 mm Low 10
9 Jul 25.5 °C 33 % 31 km/h 0.1 mm Moderate 16
10 Jul 25.3 °C 39 % 34 km/h 2.5 mm Very low 5
11 Jul 26.2 °C 34 % 25 km/h 0.1 mm Moderate 13
12 Jul 23.9 °C 39 % 28 km/h 0.0 mm Moderate 15
13 Jul after 19.9 °C 36 % 36 km/h 0.9 mm Moderate 11
14 Jul after 21.0 °C 28 % 26 km/h 0.0 mm Moderate 15
15 Jul after 16.9 °C 52 % 39 km/h 18.3 mm Very low 0

Its twins: fires that started in the same weather

It started with an FWI of 4.8, a minimum humidity of 51% and rain the day before. Fires in the area that started in weather like this since 2016: 21.

FWI at the start 4.8
Minimum humidity 51 %
Days without rain 0
this fire chosen twins rest of the area
Almost identicalSimilar

Outlines of the closest twins

Paradise Fork Fire, July 2016
563 ha 2 days FWI 2.2 Min. humidity 49 % 36 km away, in 2016

First rain (1 mm or more) after it ended: 2.0 mm on 17 Jul.

What happened to them

8 days
median duration
2,464 ha
median area
76 %
went past 1,000 ha
4.9 mm
rain at the end (median; 21 of 21 had it)

It burned an area similar to its twins (3,487 ha against a median of 2,464 ha) and lasted 6 days, against 8 days.

All of them had rain in the ten days after the end: the first rainy day brought a median of 4.9 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

18.3 mmfirst rain
15 Jul3 days after it ended
34km/h · max. gust

It was considered over on 12 Jul, and on 15 Jul 18.3 mm fell. We do not know whether the rain or the firefighters put it out. Twins with rain when they ended: 21 of 21, with a median of 4.9 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 2022
After · 19 Jul 2022

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 · 188Every 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 Sischu Fire last?
The official perimeter only gives the start date (7 July 2022). The end comes from the heat detections inside the perimeter: it burned until 12 July 2022 (6 days from 7 July 2022), 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 3,487 hectares (34.9 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?
The fire only entered Yukon-Koyukuk (3,332 ha, 0.0 %).
What was the weather like?
During the fire the temperature reached 26.2 °C, humidity dropped to 33 % and gusts hit 34 km/h. The fire danger index (FWI) reached 16, 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.
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: 21. Their median duration was 8 days and their median area 2,464 ha; 76 % went past 1,000 ha. All of them had rain in the ten days after the end: the first rainy day brought a median of 4.9 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. 188 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.