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US · United States · –

Jack Knife 0440 Rn Fire, June 2018 Sherman, Gilliam

Out · last detection 24 Jun 2018, 09:34 UTC

The fire started on 22 June 2018 in Sherman, United States, and satellites saw it burning for 3 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 6,507 hectares, spread across 2 counties.

It is the 96th largest in Oregon since 2016 (of 325 with a page). Number 89 in United States in 2018, of 511.

The power measured by the satellite is low (20.2 MW in the strongest hotspot), more typical of grass or stubble burning, or a slow surface fire, than of a large crown fire.

Burnt area
6,507ha
official perimeter (MTBS / NIFC)
Duration
≈ 3days
22 Jun 2018 – 24 Jun 2018
Counties hit
2
counties
Started on
22 Jun
2018
Heat detections
77
in a single hotspot: 20 MW
Danger at start
47
Very high · FWI index
Average daily power
175MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 22 Jun24 Jun
24 Jun 2018

How it evolved, day by day

22 Jun 2018 · 200 MW · 22 23 Jun 2018 · 325 MW · 54 24 Jun 2018 · 1 MW · 1
22 Jun 23 Jun 24 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

34°high
55km/h · peak gust
10%lowest humidity

It had gone 5 days without rain (1 mm or more) when it started.

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 4.1% of the area of London (65 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. Sherman where it started
    6,496 ha reached on 22 Jun
    3.0 %
  2. 10 ha reached on 23 Jun
    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 area0.23 ha
Residents< 20

Inside the perimeter there were about 0.23 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)

Started with Strong wind: 27 % of the area in United States

Day High Min. humidity Peak gust Rain Danger (FWI)
22 Jun 26.0 °C 27 % 55 km/h 0.0 mm Very high 47
23 Jun 25.5 °C 27 % 35 km/h 0.0 mm Very high 38
24 Jun 34.2 °C 10 % 28 km/h 0.0 mm Very high 49
25 Jun after 24.5 °C 24 % 51 km/h 0.0 mm Extreme 50
26 Jun after 25.2 °C 20 % 29 km/h 0.0 mm Very high 38
27 Jun after 27.1 °C 16 % 51 km/h 0.0 mm Extreme 53
28 Jun after 22.4 °C 31 % 54 km/h 0.8 mm High 35
29 Jun after 26.2 °C 26 % 48 km/h 0.0 mm Very high 40
30 Jun after 28.2 °C 21 % 54 km/h 0.0 mm Extreme 51
1 Jul after 26.7 °C 19 % 56 km/h 0.0 mm Extreme 52
2 Jul after 20.8 °C 25 % 54 km/h 0.0 mm Very high 47
3 Jul after 24.0 °C 19 % 31 km/h 0.0 mm High 36
4 Jul after 28.6 °C 16 % 52 km/h 0.0 mm Extreme 56

Its twins: fires that started in the same weather

It started with an FWI of 46.9, a minimum humidity of 27% and 5 days without rain. Fires in the area that started in weather like this since 2016: 35.

FWI at the start 46.9
Minimum humidity 27 %
Days without rain 5
this fire chosen twins rest of the area
Almost identicalSimilar

Outlines of the closest twins

0604 Elk Lane Fire, August 2024
2,110 ha 3 days FWI 49.7 Min. humidity 25 % 85 km away, in 2024

First rain (1 mm or more) after it ended: 3.2 mm on 15 Aug.

What happened to them

2 days
median duration
2,498 ha
median area
86 %
went past 1,000 ha
2.2 mm
rain at the end (median; 17 of 35 had it)

It was 2.6 times larger than the median of its twins and lasted 3 days, against 2 days.

Only 5 of its 35 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. In 18 of 35, not even 1 mm fell in the ten days after the end: they went out without rain. In the rest, the first rainy day brought a median of 2.2 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

—first rain
—no rain in ten days
55km/h · max. gust

It was considered over on 24 Jun, and not even 1 mm fell in the following ten days: it went out without rain. Twins with rain when they ended: 17 of 35, with a median of 2.2 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 · 15 Jun 2018
After · 1 Jul 2018

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 · 77Every 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 Jack Knife 0440 Rn Fire last?
The official perimeter only gives the start date (22 June 2018). The end comes from the heat detections inside the perimeter: it burned until 24 June 2018 (3 days from 22 June 2018), 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 6,507 hectares (65.1 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?
The fire entered 2 counties: Sherman (6,496 ha, 3.0 %); Gilliam (10 ha, 0.0 %).
What was the weather like?
During the fire the temperature reached 34.2 °C, humidity dropped to 10 % and gusts hit 55 km/h. The fire danger index (FWI) reached 49, 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.
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: 35. Their median duration was 2 days and their median area 2,498 ha; 86 % went past 1,000 ha. Only 5 of its 35 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. In 18 of 35, not even 1 mm fell in the ten days after the end: they went out without rain. In the rest, the first rainy day brought a median of 2.2 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. 77 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.