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Horse Park Fire, May 2018 San Miguel

Out · last detection 29 May 2018, 20:45 UTC

The fire started on 26 May 2018 in San Miguel, United States, and satellites saw it burning for 4 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 547 hectares, spread across a single county.

It is the 142th largest in Colorado since 2016 (of 167 with a page). Number 445 in United States in 2018, of 511.

The power measured by the satellite is low (19.7 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: Sieber · 2020Turner Gulch · 2025West Guard · 2018Doe Canyon · 2019

Burnt area
547ha
official perimeter (MTBS / NIFC)
Duration
≈ 4days
26 May 2018 – 29 May 2018
Counties hit
1
counties
Started on
26 May
2018
Heat detections
31
in a single hotspot: 20 MW
Danger at start
86
Very extreme · FWI index
Average daily power
68MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 26 May29 May
29 May 2018

How it evolved, day by day

27 May 2018 · 120 MW · 13 28 May 2018 · 27 MW · 13 29 May 2018 · 58 MW · 5
27 May 28 May 29 May

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
74km/h · peak gust
7%lowest humidity

It had gone 22 days without rain (1 mm or more) when it started. Rain came after the fire: 2.6 mm on 3 Jun.

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 0.3% of the area of London (5.5 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. San Miguel where it started
    553 ha reached on 27 May
    0.2 %

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)

Started with Extreme FWI: 36 % of the area in United States Strong wind: 27 % of the area in United States Very dry air: 40 % of the area in United States

Day High Min. humidity Peak gust Rain Danger (FWI)
26 May 25.8 °C 7 % 74 km/h 0.0 mm Very extreme 86
27 May 22.4 °C 9 % 54 km/h 0.0 mm Very extreme 72
28 May 20.0 °C 13 % 46 km/h 0.0 mm Extreme 62
29 May 22.9 °C 14 % 37 km/h 0.0 mm Very high 49
30 May after 21.6 °C 16 % 48 km/h 0.1 mm Extreme 56
31 May after 25.8 °C 5 % 64 km/h 0.0 mm Very extreme 81
1 Jun after 23.9 °C 7 % 53 km/h 0.0 mm Very extreme 76
2 Jun after 26.8 °C 6 % 33 km/h 0.0 mm Extreme 53
3 Jun after 20.5 °C 21 % 63 km/h 2.6 mm High 36

Its twins: fires that started in the same weather

It started with an FWI of 85.5, a minimum humidity of 7% and 22 days without rain. Fires in the area that started in weather like this since 2016: 5.

FWI at the start 85.5
Minimum humidity 7 %
Days without rain 22
this fire chosen twins rest of the area
Almost identicalSimilar

Outlines of the closest twins

Sieber Fire, June 2020
419 ha 1 day FWI 80.9 Min. humidity 8 % 128 km away, in 2020

First rain (1 mm or more) after it ended: 11.1 mm on 6 Jun.

See its page Compare with this fire

What happened to them

Fires in the area that started in similar weather: 5. 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

2.6 mmfirst rain
3 Jun5 days after it ended
74km/h · max. gust

It was considered over on 29 May, and on 3 Jun 2.6 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 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 · 19 May 2018
After · 5 Jun 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 · 31Every 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 Horse Park Fire last?
The official perimeter only gives the start date (26 May 2018). The end comes from the heat detections inside the perimeter: it burned until 29 May 2018 (4 days from 26 May 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 547 hectares (5.5 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?
The fire only entered San Miguel (553 ha, 0.2 %).
What was the weather like?
During the fire the temperature reached 25.8 °C, humidity dropped to 7 % and gusts hit 74 km/h. The fire danger index (FWI) reached 86, class Very 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

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 With cross-checks and a citable version

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. 31 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.