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Pioneer Fire, July 2016 Boise, Valley

Out · last detection 17 Sept 2016, 09:29 UTC

The fire started on 18 July 2016 in Boise, United States, and satellites saw it burning for 62 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 76,691 hectares, spread across 2 counties.

It is the largest fire in Idaho since 2016 (of 379 with a page). Number 2 in United States in 2016, of 475.

Compare with…

Suggestions: Rough · 2016Buck · 2016Crooked · 2026Wapiti · 2018

Burnt area
76,691ha
official perimeter (MTBS / NIFC)
Duration
≈ 62days
18 Jul 2016 – 17 Sept 2016
Counties hit
2
counties
Started on
18 Jul
2016
Heat detections
12,240
in a single hotspot: 889 MW
Danger at start
31
High · FWI index
Average daily power
3.3GW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 18 Jul17 Sept
17 Sept 2016

How it evolved, day by day

19 Jul 2016 · 566 MW · 29 20 Jul 2016 · 71 MW · 15 21 Jul 2016 · 3,578 MW · 57 22 Jul 2016 · 1,279 MW · 44 23 Jul 2016 · 394 MW · 82 24 Jul 2016 · 1,163 MW · 66 25 Jul 2016 · 1,340 MW · 98 26 Jul 2016 · 4,229 MW · 134 27 Jul 2016 · 1,837 MW · 232 28 Jul 2016 · 4,987 MW · 244 29 Jul 2016 · 7,338 MW · 390 30 Jul 2016 · 10,253 MW · 326 31 Jul 2016 · 15,830 MW · 546 1 Aug 2016 · 7,070 MW · 545 2 Aug 2016 · 3,675 MW · 325 3 Aug 2016 · 2,498 MW · 415 4 Aug 2016 · 2,482 MW · 301 5 Aug 2016 · 4,871 MW · 74 6 Aug 2016 · 519 MW · 50 7 Aug 2016 · 1,556 MW · 242 8 Aug 2016 · 1,531 MW · 221 9 Aug 2016 · 460 MW · 78 10 Aug 2016 · 113 MW · 63 11 Aug 2016 · 1,757 MW · 117 12 Aug 2016 · 1,719 MW · 210 13 Aug 2016 · 851 MW · 164 14 Aug 2016 · 3,408 MW · 211 15 Aug 2016 · 10,221 MW · 399 16 Aug 2016 · 4,282 MW · 312 17 Aug 2016 · 2,099 MW · 205 18 Aug 2016 · 4,087 MW · 304 19 Aug 2016 · 6,337 MW · 470 20 Aug 2016 · 1,486 MW · 222 21 Aug 2016 · 2,733 MW · 211 22 Aug 2016 · 5,492 MW · 491 23 Aug 2016 · 2,252 MW · 240 24 Aug 2016 · 1,930 MW · 245 25 Aug 2016 · 1,553 MW · 157 26 Aug 2016 · 2,028 MW · 156 27 Aug 2016 · 6,427 MW · 211 28 Aug 2016 · 2,671 MW · 336 29 Aug 2016 · 7,962 MW · 252 30 Aug 2016 · 10,841 MW · 678 31 Aug 2016 · 5,903 MW · 570 1 Sept 2016 · 22,854 MW · 614 2 Sept 2016 · 542 MW · 198 3 Sept 2016 · 4 MW · 4 4 Sept 2016 · 11 MW · 7 5 Sept 2016 · 10 MW · 7 6 Sept 2016 · 20 MW · 14 7 Sept 2016 · 143 MW · 36 8 Sept 2016 · 149 MW · 32 9 Sept 2016 · 2,024 MW · 137 10 Sept 2016 · 1,562 MW · 165 11 Sept 2016 · 860 MW · 162 12 Sept 2016 · 356 MW · 104 13 Sept 2016 · 110 MW · 19 16 Sept 2016 · 18 MW · 2 17 Sept 2016 · 1 MW · 1
19 Jul 28 Jul 6 Aug 15 Aug 24 Aug 1 Sept 2 Sept 11 Sept

Fire radiative power detected each day, in megawatts, and number of hotspots. The magenta bar marks the peak day.

The weather it burned in

30°high
57km/h · peak gust
9%lowest humidity

It had gone 5 days without rain (1 mm or more) when it started. Rain came after the fire: 4.2 mm on 18 Sept.

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 48% of the area of London (767 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. Boise where it started
    62,743 ha reached on 19 Jul
    13 %
  2. Valley
    13,980 ha reached on 7 Aug
    1.4 %

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 area0.24 ha
Residents< 20

Inside the perimeter there were about 0.24 hectares of 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 25.4 °C 14 % 52 km/h 0.0 mm High 31
19 Jul 24.8 °C 17 % 50 km/h 0.0 mm High 31
20 Jul 25.8 °C 19 % 43 km/h 0.0 mm High 30
21 Jul 30.0 °C 15 % 44 km/h 0.0 mm High 33
22 Jul 24.3 °C 20 % 49 km/h 0.0 mm High 34
23 Jul 22.6 °C 21 % 39 km/h 0.0 mm High 30
24 Jul 27.0 °C 18 % 37 km/h 0.0 mm High 31
25 Jul 29.4 °C 14 % 39 km/h 0.0 mm High 35
26 Jul 29.3 °C 15 % 39 km/h 0.0 mm High 36
27 Jul 30.4 °C 16 % 41 km/h 0.0 mm High 37
28 Jul 29.9 °C 12 % 43 km/h 0.0 mm Very high 39
29 Jul 30.1 °C 14 % 45 km/h 0.0 mm Very high 41
30 Jul 29.8 °C 15 % 55 km/h 0.2 mm Very high 45
31 Jul 26.8 °C 9 % 49 km/h 0.0 mm Very high 44
1 Aug 26.9 °C 12 % 43 km/h 0.0 mm Very high 42
2 Aug 27.2 °C 15 % 49 km/h 0.0 mm Very high 44
3 Aug 22.4 °C 18 % 39 km/h 0.0 mm Very high 38
4 Aug 26.2 °C 14 % 35 km/h 0.0 mm High 37
5 Aug 26.2 °C 17 % 38 km/h 0.0 mm Very high 40
6 Aug 25.6 °C 16 % 57 km/h 0.2 mm Very high 46
7 Aug 23.7 °C 21 % 55 km/h 0.5 mm Very high 42
8 Aug 22.2 °C 22 % 49 km/h 0.0 mm Very high 38
9 Aug 15.7 °C 33 % 52 km/h 0.2 mm High 32
10 Aug 20.5 °C 24 % 33 km/h 0.0 mm High 27
11 Aug 23.0 °C 23 % 39 km/h 0.0 mm High 30
12 Aug 25.8 °C 16 % 41 km/h 0.0 mm High 36
13 Aug 27.3 °C 15 % 40 km/h 0.0 mm High 38
14 Aug 27.8 °C 14 % 46 km/h 0.4 mm Very high 41
15 Aug 29.7 °C 12 % 40 km/h 0.0 mm Very high 42
16 Aug 29.9 °C 11 % 35 km/h 0.0 mm Very high 44
17 Aug 27.7 °C 15 % 37 km/h 0.0 mm Very high 43
18 Aug 28.2 °C 13 % 43 km/h 0.0 mm Very high 47
19 Aug 27.1 °C 16 % 35 km/h 0.0 mm Very high 43
20 Aug 26.8 °C 18 % 32 km/h 0.0 mm Very high 41
21 Aug 26.9 °C 13 % 46 km/h 0.0 mm Very high 46
22 Aug 21.8 °C 14 % 51 km/h 0.0 mm Very high 46
23 Aug 21.2 °C 17 % 40 km/h 0.0 mm Very high 40
24 Aug 21.6 °C 17 % 38 km/h 0.0 mm Very high 39
25 Aug 21.4 °C 23 % 29 km/h 0.0 mm High 35
26 Aug 22.6 °C 21 % 41 km/h 0.0 mm High 38
27 Aug 23.9 °C 18 % 45 km/h 0.0 mm Very high 39
28 Aug 25.4 °C 22 % 38 km/h 0.0 mm High 37
29 Aug 27.0 °C 13 % 49 km/h 0.0 mm Very high 43
30 Aug 26.7 °C 13 % 44 km/h 0.0 mm Very high 43
31 Aug 26.2 °C 15 % 37 km/h 0.0 mm Very high 41
1 Sept 24.6 °C 20 % 50 km/h 0.0 mm Very high 44
2 Sept 14.1 °C 34 % 36 km/h 0.1 mm High 30
3 Sept 16.7 °C 22 % 33 km/h 0.0 mm High 29
4 Sept 10.3 °C 37 % 23 km/h 7.3 mm Very low 1
5 Sept 14.2 °C 32 % 33 km/h 0.2 mm Low 5
6 Sept 15.9 °C 29 % 45 km/h 0.0 mm Moderate 14
7 Sept 16.9 °C 34 % 35 km/h 0.0 mm Moderate 17
8 Sept 17.7 °C 24 % 46 km/h 0.0 mm High 24
9 Sept 18.6 °C 20 % 31 km/h 0.0 mm High 26
10 Sept 21.6 °C 17 % 34 km/h 0.0 mm High 30
11 Sept 19.2 °C 20 % 50 km/h 0.0 mm High 34
12 Sept 13.4 °C 28 % 37 km/h 0.3 mm High 27
13 Sept 14.6 °C 28 % 30 km/h 0.0 mm High 25
14 Sept 9.5 °C 61 % 31 km/h 3.6 mm Very low 2
15 Sept 17.6 °C 32 % 35 km/h 0.0 mm Low 7
16 Sept 18.9 °C 26 % 35 km/h 0.0 mm Moderate 16
17 Sept 19.3 °C 20 % 51 km/h 0.5 mm High 26
18 Sept after 16.8 °C 45 % 49 km/h 4.2 mm Very low 4

Before and after, from space

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

Before · 11 Jul 2016
After · 24 Sept 2016

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 · 12,240Every 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 Pioneer Fire last?
The official perimeter only gives the start date (18 July 2016). The end comes from the heat detections inside the perimeter: it burned until 17 September 2016 (62 days from 18 July 2016), 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 76,691 hectares (766.9 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?
The fire entered 2 counties: Boise (62,743 ha, 13 %); Valley (13,980 ha, 1.4 %).
What was the weather like?
During the fire the temperature reached 30.4 °C, humidity dropped to 9 % and gusts hit 57 km/h. The fire danger index (FWI) reached 47, 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.

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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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. 12,240 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.