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Cedar Mountain Fire, July 2017 Tooele

Out · last detection 20 Jul 2017, 20:14 UTC

The fire started on 18 July 2017 in Tooele, United States, and satellites saw it burning for 3 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 8,654 hectares, spread across a single county.

It is the 18th largest in Utah since 2016 (of 165 with a page). Number 94 in United States in 2017, of 619.

Compare with…
Burnt area
8,654ha
official perimeter (MTBS / NIFC)
Duration
≈ 3days
18 Jul 2017 – 20 Jul 2017
Counties hit
1
counties
Started on
18 Jul
2017
Heat detections
108
in a single hotspot: 38 MW
Danger at start
49
Very high · FWI index
Average daily power
225MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 18 Jul20 Jul
20 Jul 2017

How it evolved, day by day

18 Jul 2017 · 549 MW · 63 19 Jul 2017 · 51 MW · 21 20 Jul 2017 · 75 MW · 24
18 Jul 19 Jul 20 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

33°high
45km/h · peak gust
14%lowest humidity

It had gone 34 days without rain (1 mm or more) when it started. Rain came after the fire: 1.1 mm on 25 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 5.5% of the area of London (87 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. Tooele where it started
    8,677 ha reached on 18 Jul
    0.5 %

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 2015
Built-up area< 0.1 ha
Residents< 20

Inside the perimeter there was no noticeable built-up land and almost nobody lived there (GHSL 2015, 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)
18 Jul 33.4 °C 14 % 31 km/h 0.0 mm Very high 49
19 Jul 31.7 °C 17 % 35 km/h 0.0 mm Extreme 59
20 Jul 32.5 °C 19 % 45 km/h 0.0 mm Extreme 56
21 Jul after 31.4 °C 16 % 31 km/h 0.0 mm Extreme 51
22 Jul after 31.4 °C 17 % 35 km/h 0.0 mm Extreme 51
23 Jul after 31.7 °C 13 % 23 km/h 0.0 mm Very high 46
24 Jul after 31.4 °C 14 % 34 km/h 0.0 mm Extreme 53
25 Jul after 26.9 °C 31 % 38 km/h 1.1 mm High 30

Before and after, from space

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

Before · 11 Jul 2017
After · 27 Jul 2017

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 · 108Every 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 Cedar Mountain Fire last?
The official perimeter only gives the start date (18 July 2017). The end comes from the heat detections inside the perimeter: it burned until 20 July 2017 (3 days from 18 July 2017), 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 8,654 hectares (86.5 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?
The fire only entered Tooele (8,677 ha, 0.5 %).
What was the weather like?
During the fire the temperature reached 33.4 °C, humidity dropped to 14 % and gusts hit 45 km/h. The fire danger index (FWI) reached 59, 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

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

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.

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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. 108 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 2015, 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.