How long did the East Fork Fire last?

The official perimeter only gives the start date (31 May 2022). The end comes from the heat detections inside the perimeter: it burned until 24 June 2022 (25 days from 31 May 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 68,554 hectares (685.5 km²). Other tallies, such as daily incident reports, may give slightly different figures.

Which counties burned?

The fire only entered Kusilvak (68,604 ha, 1.5 %).

What was the weather like?

During the fire the temperature reached 24.8 °C, humidity dropped to 21 % and gusts hit 51 km/h. The fire danger index (FWI) reached 26, 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.

US · United States · 2022-05-31 → 2022-06-24

East Fork Fire, May 2022 Kusilvak

Out · last detection 24 Jun 2022, 22:53 UTC

The fire started on 31 May 2022 in Kusilvak, United States, and satellites saw it burning for 25 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 68,554 hectares, spread across a single county.

It is the 7th largest in Alaska since 2016 (of 472 with a page). Number 7 in United States in 2022, of 493.

Compare with…

Suggestions: Allen · 2017

Burnt area: 68,554ha; official perimeter (MTBS / NIFC)
Duration: ≈ 25days; 31 May 2022 – 24 Jun 2022
Counties hit: 1; counties
Started on: 31 May; 2022
Heat detections: 4,527; in a single hotspot: 289 MW
Danger at start: 0; Very low · FWI index
Average daily power: 2.5GW; detected power per day, on average

HOTSPOTS BY DAY 31 May24 Jun

Play back 24 Jun 2022

How it evolved, day by day

1 Jun 4 Jun 7 Jun 10 Jun 13 Jun 16 Jun 20 Jun

Fire radiative power detected each day, in megawatts, and number of hotspots. The magenta bar marks the peak day.

The weather it burned in

25°high

51km/h · peak gust

21%lowest humidity

It had gone 0 days without rain (1 mm or more) when it started. Rain came after the fire: 1.4 mm on 25 Jun.

This area had burned before

No earlier perimeters overlap this fire since 2016, when the satellite record begins.

How big is it?

It burned the equivalent of 43% of the area of London (686 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

Kusilvak where it started

68,604 ha reached on 1 Jun

1.5 %

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)
31 May	18.7 °C	55 %	23 km/h	7.4 mm	Very low 0
1 Jun	17.9 °C	40 %	25 km/h	0.0 mm	Very low 2
2 Jun	20.5 °C	38 %	28 km/h	0.0 mm	Low 6
3 Jun	21.0 °C	29 %	35 km/h	0.0 mm	Moderate 12
4 Jun	20.4 °C	38 %	37 km/h	0.0 mm	Moderate 14
5 Jun	22.7 °C	33 %	34 km/h	1.0 mm	Low 11
6 Jun	24.8 °C	21 %	32 km/h	0.0 mm	Moderate 17
7 Jun	24.5 °C	22 %	32 km/h	0.0 mm	Moderate 20
8 Jun	23.2 °C	25 %	34 km/h	0.2 mm	Moderate 21
9 Jun	21.7 °C	27 %	33 km/h	0.0 mm	Moderate 20
10 Jun	18.2 °C	26 %	51 km/h	0.0 mm	High 26
11 Jun	14.4 °C	31 %	36 km/h	0.0 mm	Moderate 20
12 Jun	8.9 °C	51 %	31 km/h	0.0 mm	Moderate 14
13 Jun	8.9 °C	44 %	47 km/h	0.3 mm	Moderate 17
14 Jun	11.3 °C	49 %	38 km/h	0.0 mm	Moderate 14
15 Jun	16.1 °C	37 %	28 km/h	0.0 mm	Moderate 13
16 Jun	18.4 °C	45 %	35 km/h	0.8 mm	Low 10
17 Jun	16.9 °C	60 %	30 km/h	2.4 mm	Very low 3
18 Jun	17.7 °C	57 %	24 km/h	3.7 mm	Very low 1
19 Jun	18.0 °C	60 %	21 km/h	6.5 mm	Very low 0
20 Jun	19.4 °C	41 %	28 km/h	0.1 mm	Very low 2
21 Jun	14.9 °C	57 %	38 km/h	0.0 mm	Very low 5
22 Jun	11.2 °C	70 %	33 km/h	0.3 mm	Very low 5
23 Jun	14.2 °C	65 %	20 km/h	0.0 mm	Very low 5
24 Jun	21.4 °C	40 %	34 km/h	0.0 mm	Low 11
25 Jun after	20.1 °C	40 %	44 km/h	1.4 mm	Low 10

Before and after, from space

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

↔

Before · 24 May 2022

After · 1 Jul 2022

Before After

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 · 4,527Every 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 time	Satellite	FRP (MW)	Lat	Lon

Other fires nearby

1,012 haAllen KusilvakJune 2017 · 2 days · 39 km away

All fires in United States ›

Frequently asked questions

How long did the East Fork Fire last?: The official perimeter only gives the start date (31 May 2022). The end comes from the heat detections inside the perimeter: it burned until 24 June 2022 (25 days from 31 May 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 68,554 hectares (685.5 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?: The fire only entered Kusilvak (68,604 ha, 1.5 %).
What was the weather like?: During the fire the temperature reached 24.8 °C, humidity dropped to 21 % and gusts hit 51 km/h. The fire danger index (FWI) reached 26, 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.

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

NASA FIRMS ↗
NIFC · Fire maps ↗

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

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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. 4,527 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.

Where it burned