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US · United States ·

Shaw Springs Fire, August 2017 Box Elder

Out · last measured on 23 Aug 2017

The fire started on 23 August 2017 in Box Elder, United States, and satellites saw it burning for 1 day. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 993 hectares, spread across a single county.

It is the 107th largest in Utah since 2016 (of 165 with a page). Number 390 in United States in 2017, of 619.

We have the official perimeter (MTBS / NIFC) for this fire, but the VIIRS sensors did not capture it in enough detail: no day-by-day evolution, but the split by county is there.

Burnt area
993ha
official perimeter (MTBS / NIFC)
Duration
1day
23 Aug 2017 – 23 Aug 2017
Counties hit
1
counties
Started on
23 Aug
2017
Danger at start
19
Moderate · FWI index

Where it burned

The weather it burned in

30°high
32km/h · peak gust
29%lowest humidity

It had gone 8 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 0.6% of the area of London (9.9 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. Box Elder where it started
    993 ha
    0.1 %

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)
23 Aug 29.6 °C 29 % 32 km/h 2.3 mm Moderate 19
24 Aug after 31.9 °C 18 % 30 km/h 0.0 mm High 35
25 Aug after 33.6 °C 19 % 26 km/h 0.1 mm Very high 42
26 Aug after 35.7 °C 12 % 25 km/h 0.0 mm Very high 46
27 Aug after 36.1 °C 4 % 20 km/h 0.0 mm Extreme 50
28 Aug after 35.7 °C 10 % 26 km/h 0.5 mm Very high 50
29 Aug after 35.6 °C 11 % 28 km/h 0.4 mm Extreme 65
30 Aug after 32.8 °C 20 % 32 km/h 0.1 mm Very high 50
31 Aug after 30.5 °C 30 % 28 km/h 0.8 mm High 32
1 Sept after 32.3 °C 13 % 18 km/h 0.0 mm High 38
2 Sept after 34.9 °C 6 % 23 km/h 0.0 mm Very high 48

Its twins: fires that started in the same weather

It started with an FWI of 19.4, a minimum humidity of 29% and 8 days without rain. Fires in the area that started in weather like this since 2016: 17.

FWI at the start 19.4
Minimum humidity 29 %
Days without rain 8
this fire chosen twins rest of the area
Almost identicalSimilar

Outlines of the closest twins

Cowboy Fire, September 2017
679 ha 1 day FWI 20.9 Min. humidity 29 % 205 km away, in 2017

First rain (1 mm or more) after it ended: 7.2 mm on 15 Sept.

What happened to them

2 days
median duration
1,009 ha
median area
53 %
went past 1,000 ha
3.6 mm
rain at the end (median; 11 of 17 had it)

It burned an area similar to its twins (993 ha against a median of 1,009 ha) and lasted 1 day, against 2 days.

In 6 of 17, 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 3.6 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
32km/h · max. gust

It was considered over on 23 Aug, and not even 1 mm fell in the following ten days: it went out without rain. Twins with rain when they ended: 11 of 17, with a median of 3.6 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 · 16 Aug 2017
After · 30 Aug 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.

Other fires nearby

All fires in United States

Frequently asked questions

How long did the Shaw Springs Fire last?
It burned between 23 August 2017 and 23 August 2017: 1 day, according to the start date recorded by United States agencies (MTBS / NIFC) and the heat detections seen by satellite.
How much area did it burn?
The official perimeter published by United States agencies (MTBS / NIFC) is 993 hectares (9.9 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?
The fire only entered Box Elder (993 ha, 0.1 %).
What was the weather like?
During the fire the temperature reached 29.6 °C, humidity dropped to 29 % and gusts hit 32 km/h. The fire danger index (FWI) reached 19, class Moderate.
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: 17. Their median duration was 2 days and their median area 1,009 ha; 53 % went past 1,000 ha. In 6 of 17, 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 3.6 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
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.
  • Dates from the perimeter: the VIIRS detections inside it did not change them. No 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.