How long did the County Line Fire last?

The official perimeter only gives the start date (15 March 2018). The end comes from the heat detections inside the perimeter: it burned until 19 March 2018 (5 days from 15 March 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 7,116 hectares (71.2 km²). Other tallies, such as daily incident reports, may give slightly different figures.

Which counties burned?

The fire entered 3 counties: Hartley (5,714 ha, 1.5 %); Moore (1,375 ha, 0.6 %); Oldham (18 ha, 0.0 %).

What was the weather like?

During the fire the temperature reached 25.2 °C, humidity dropped to 8 % and gusts hit 79 km/h. The fire danger index (FWI) reached 63, class Extreme.

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 · 2018-03-15 → 2018-03-19

County Line Fire, March 2018 Hartley, Moore, Oldham

Out · last detection 19 Mar 2018, 08:15 UTC

The fire started on 15 March 2018 in Hartley, United States, and satellites saw it burning for 5 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 7,116 hectares, spread across 3 counties.

It is the 26th largest in Texas since 2016 (of 327 with a page). Number 86 in United States in 2018, of 511.

The power measured by the satellite is low (6.0 MW in the strongest hotspot), more typical of grass or stubble burning, or a slow surface fire, than of a large crown fire.

Compare with…

Suggestions: Parker Creek · 2021 Channing · 2019 Lit Ranch · 2017 Old Muddy Rd · 2018

Burnt area: 7,116ha; official perimeter (MTBS / NIFC)
Duration: ≈ 5days; 15 Mar 2018 – 19 Mar 2018
Counties hit: 3; counties
Started on: 15 Mar; 2018
Heat detections: 14; in a single hotspot: 6 MW
Danger at start: 55; Extreme · FWI index
Average daily power: 16MW; detected power per day, on average

HOTSPOTS BY DAY 15 Mar19 Mar

Play back 19 Mar 2018

How it evolved, day by day

16 Mar 19 Mar

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

79km/h · peak gust

8%lowest humidity

It had gone more than two months without rain (1 mm or more) when it started. Rain came after the fire: 1.0 mm on 27 Mar.

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 4.5% of the area of London (71 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

Hartley where it started

5,714 ha reached on 16 Mar

1.5 %
Moore

1,375 ha reached on 16 Mar

0.6 %
Oldham

18 ha

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 area0.38 ha

Residents< 20

Inside the perimeter there were about 0.38 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)

Day	High	Min. humidity	Peak gust	Rain	Danger (FWI)
15 Mar	25.2 °C	13 %	66 km/h	0.0 mm	Extreme 55
16 Mar	21.4 °C	8 %	65 km/h	0.0 mm	Extreme 63
17 Mar	18.9 °C	20 %	44 km/h	0.0 mm	Very high 39
18 Mar	21.5 °C	14 %	79 km/h	0.0 mm	Extreme 63
19 Mar	12.1 °C	23 %	65 km/h	0.0 mm	Extreme 50
20 Mar after	15.6 °C	18 %	37 km/h	0.0 mm	High 30
21 Mar after	19.1 °C	16 %	38 km/h	0.0 mm	High 35
22 Mar after	25.3 °C	15 %	30 km/h	0.0 mm	High 36
23 Mar after	30.4 °C	10 %	71 km/h	0.0 mm	Very extreme 72
24 Mar after	22.0 °C	21 %	46 km/h	0.0 mm	Very high 48
25 Mar after	25.6 °C	14 %	60 km/h	0.0 mm	Extreme 55
26 Mar after	20.4 °C	17 %	56 km/h	0.0 mm	Extreme 51
27 Mar after	13.1 °C	44 %	54 km/h	1.0 mm	High 23

Before and after, from space

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

↔

Before · 8 Mar 2018

After · 26 Mar 2018

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 · 14Every 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

All fires in United States ›

Frequently asked questions

How long did the County Line Fire last?: The official perimeter only gives the start date (15 March 2018). The end comes from the heat detections inside the perimeter: it burned until 19 March 2018 (5 days from 15 March 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 7,116 hectares (71.2 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?: The fire entered 3 counties: Hartley (5,714 ha, 1.5 %); Moore (1,375 ha, 0.6 %); Oldham (18 ha, 0.0 %).
What was the weather like?: During the fire the temperature reached 25.2 °C, humidity dropped to 8 % and gusts hit 79 km/h. The fire danger index (FWI) reached 63, class Extreme.
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.

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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.

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What really happened?

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How we know this

Perimeter: MTBS (US Geological Survey and US Forest Service), official; 2 polygons grouped in this page.
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. 14 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