Burned area
satellite only56,379ha
Perimeter published by MTBS (USGS/USFS).
- Source
- MTBS (USGS/USFS)
- Date
- 23 Jun 2019 – 30 Jul 2019
+− cross-check
No official record is matched to this page to compare it with.
US · United States · –
Hurst Creek Fire, June 2019 Yukon-Koyukuk
Out · last detection 30 Jul 2019, 22:28 UTC
The fire started on 23 June 2019 in Yukon-Koyukuk, United States, and satellites saw it burning for 38 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 56,379 hectares, spread across a single county.
It is the 11th largest in Alaska since 2016 (of 472 with a page). Number 5 in United States in 2019, of 367.
Use this data
Compare with…
Use this data
Fire page data · version 2026-10-24matches the official recordwith caveatssatellite onlymodel
When copying, the sentence is
Tick the figures you want: they make up the lede and the CSV.
Duration by satellite
satellite only38days
23 Jun 2019 to 30 Jul 2019: first and last day with fire on the page.
- Source
- MTBS (USGS/USFS) · NASA FIRMS · VIIRS
- Date
- last detection: 30 Jul 2019, 22:28 UTC
+− cross-check
Satellites pass a few times a day and cloud or smoke can hide the fire: a lack of detections is not an official extinction. Each country’s emergency service declares a fire contained or out.
Start
satellite only23 Jun 2019
First day with fire seen by the satellites or the perimeter.
- Source
- MTBS (USGS/USFS) · NASA FIRMS · VIIRS
- Date
- 23 Jun 2019
+− cross-check
No official record is matched to this page, so the alert time and the cause are not known here.
Hotspots
satellite only6,112
VIIRS detections at 375 m. Most intense hotspot: 355 MW.
- Source
- NASA FIRMS · VIIRS (Suomi NPP)
- Date
- 23 Jun 2019 – 30 Jul 2019
+− cross-check
There is no official record to compare with. Each hotspot is a pixel detected in one satellite pass, not a separate fire.
The worst day
satellite only16,892MW
Total radiative power on 8 July 2019; hotspots that day: 1,370.
- Source
- NASA FIRMS · VIIRS (FRP)
- Date
- 8 Jul 2019
+− cross-check
Fire radiative power (FRP) measures the energy the fire gives off when the satellite passes. Added up by day, it compares intensity, not area.
Danger at the start
model1.0FWI · very low
Fire Weather Index (Canadian system) computed by WorldFires for the day the fire started. Consecutive days without rain before: 0.
- Source
- WorldFires calculation (Canadian FWI system)
- Date
- 23 Jun 2019, local noon
- Model
- ERA5 0,25° (ECMWF · Copernicus C3S) · Open-Meteo.com
+− cross-check
This is an index computed from weather model data, not a measurement of the fire nor an official warning. Danger warnings are issued by each country’s authority. Emergency number and official warnings
Weather during the fire
model30.4°C · 29% RH
High of 30.4 °C and minimum humidity of 29% on 8 July 2019; gusts of 47 km/h on 30 June 2019.
- Source
- weather model at the fire’s grid cell
- Date
- 23 Jun 2019 – 30 Jul 2019
- Model
- ERA5 0,25° (ECMWF · Copernicus C3S) · Open-Meteo.com
+− cross-check
These are model values for a cell of about 25 km, not from a weather station: they may differ from what was measured on the ground.
This page’s change log has been kept since 24 October 2026: every night what it publishes is compared and the difference is logged. Anything earlier is reconstructed from each source’s date and marked as reconstructed.
Show
-
· reconstructed weatherWeather and FWI computed from the ERA5 reanalysis
-
· reconstructed GHSLPopulation and built-up area computed
What was saved on 24 October 2026
Every night a snapshot of what the page shows is saved. If anything changes, it appears in the list as a log entry.
- Area
- 56,379 ha
- Dates
- 23 Jun 2019 – 30 Jul 2019
- Name
- Hurst Creek
- Official record
- —
Versioned permanent link
https://worldfires.org/en/fire/hurst-creek-fire-2019-06?v=2026-10-24A version keeps the area, dates, name and official record; the area as it was logged (changes under 2% are not logged). The map, hotspots and weather always show today’s data.
Citation
A lede of about 60 words figures only, no adjectives
CSV for this fire hurst-creek-fire-2019-06.csv · daily, no individual hotspots
| fecha | focos_viirs | frp_mw | tmax_c | tmin_c | hr_min_pct | viento_max_kmh | racha_max_kmh | precip_mm | fwi | clase_fwi | dentro_del_incendio |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 2019-06-23 | 6 | 102 | 20.4 | 11.3 | 43 | 9.3 | 26.6 | 0 | 1 | muy_bajo | 1 |
| 2019-06-24 | 8 | 86 | 21.5 | 12.1 | 46 | 7 | 15.1 | 0 | 3.2 | muy_bajo | 1 |
| 2019-06-25 | 45 | 304 | 23.8 | 15.3 | 37 | 4.8 | 13 | 0 | 6.3 | bajo | 1 |
| 2019-06-26 | 21 | 148 | 22.8 | 15.2 | 58 | 12.1 | 36.4 | 0 | 8.2 | bajo | 1 |
| 2019-06-27 | 100 | 1,027 | 26.5 | 15.1 | 31 | 10.5 | 27.4 | 0 | 12 | moderado | 1 |
| 2019-06-28 | 417 | 10,170 | 27.6 | 15.4 | 35 | 9.9 | 25.6 | 0 | 12.8 | moderado | 1 |
| 2019-06-29 | 600 | 9,002 | 23.7 | 16.1 | 54 | 10.9 | 27.7 | 0 | 11 | bajo | 1 |
| 2019-06-30 | 3 | 6 | 20.8 | 12.8 | 58 | 18.7 | 47.2 | 0.8 | 8.6 | bajo | 1 |
| 2019-07-01 | 17 | 87 | 16.7 | 10 | 50 | 11.9 | 29.9 | 0 | 8.2 | bajo | 1 |
| 2019-07-02 | 0 | 0 | 18.9 | 11.3 | 65 | 13.4 | 36.7 | 1.7 | 3.1 | muy_bajo | 1 |
| 2019-07-03 | 0 | 0 | 18.6 | 13.2 | 66 | 15.1 | 38.2 | 2.3 | 2 | muy_bajo | 1 |
| 2019-07-04 | 39 | 297 | 21.6 | 12.1 | 60 | 7.6 | 21.2 | 0 | 2.7 | muy_bajo | 1 |
| 2019-07-05 | 122 | 1,286 | 26.6 | 12.5 | 38 | 10.1 | 26.3 | 0 | 9.2 | bajo | 1 |
| 2019-07-06 | 305 | 3,543 | 27.6 | 15 | 39 | 10 | 25.9 | 0 | 12.7 | moderado | 1 |
| 2019-07-07 | 617 | 8,145 | 29.6 | 16.2 | 37 | 10.8 | 28.4 | 0 | 15.3 | moderado | 1 |
| 2019-07-08 | 1,370 | 16,892 | 30.4 | 16.5 | 29 | 14 | 36 | 0 | 20.6 | moderado | 1 |
| 2019-07-09 | 919 | 11,011 | 28.7 | 17 | 32 | 9.6 | 18 | 0 | 19.1 | moderado | 1 |
| 2019-07-10 | 813 | 11,179 | 27.8 | 16.7 | 37 | 12.5 | 31.7 | 0.1 | 20.9 | moderado | 1 |
| 2019-07-11 | 660 | 6,678 | 23.8 | 16.7 | 75 | 13.3 | 32.4 | 9.2 | 0.2 | muy_bajo | 1 |
| 2019-07-12 | 19 | 102 | 23.2 | 15 | 51 | 12.9 | 37.1 | 3.7 | 0.8 | muy_bajo | 1 |
| 2019-07-13 | 20 | 32 | 20.9 | 14.4 | 56 | 15.5 | 42.1 | 0 | 3.3 | muy_bajo | 1 |
| 2019-07-14 | 3 | 19 | 21.2 | 13.7 | 53 | 8.3 | 16.6 | 1.3 | 2.5 | muy_bajo | 1 |
| 2019-07-15 | 0 | 0 | 21 | 12.7 | 63 | 6.1 | 20.2 | 8.6 | 0.1 | muy_bajo | 1 |
| 2019-07-16 | 6 | 26 | 21.7 | 11.1 | 48 | 10.6 | 24.8 | 1.5 | 0.9 | muy_bajo | 1 |
| 2019-07-17 | 0 | 0 | 20.6 | 13.6 | 55 | 13.7 | 34.2 | 0 | 3.1 | muy_bajo | 1 |
| 2019-07-18 | 0 | 0 | 17.1 | 13.2 | 62 | 12.3 | 30.6 | 0 | 4.1 | muy_bajo | 1 |
| 2019-07-19 | 0 | 0 | 15.8 | 12.8 | 73 | 11.7 | 31 | 0.2 | 4.2 | muy_bajo | 1 |
| 2019-07-20 | 0 | 0 | 16.4 | 11.8 | 70 | 14.6 | 34.9 | 0.2 | 4.9 | muy_bajo | 1 |
| 2019-07-21 | 0 | 0 | 17.7 | 11.3 | 63 | 12.6 | 32 | 0 | 5.3 | bajo | 1 |
| 2019-07-22 | 0 | 0 | 21.7 | 12 | 56 | 6.9 | 17.3 | 0 | 5.5 | bajo | 1 |
| 2019-07-23 | 1 | 3 | 25 | 13.7 | 44 | 9.4 | 20.5 | 0 | 9 | bajo | 1 |
| 2019-07-24 | 0 | 0 | 18.7 | 14.7 | 62 | 10.8 | 23 | 5.1 | 0.5 | muy_bajo | 1 |
| 2019-07-25 | 0 | 0 | 16.8 | 12.7 | 57 | 18.8 | 47.2 | 2.9 | 0.8 | muy_bajo | 1 |
| 2019-07-26 | 0 | 0 | 14.9 | 9.9 | 58 | 13.4 | 33.1 | 5.9 | 0.1 | muy_bajo | 1 |
| 2019-07-27 | 0 | 0 | 15.7 | 9.7 | 57 | 7.2 | 20.9 | 0.6 | 0.5 | muy_bajo | 1 |
| 2019-07-28 | 0 | 0 | 18.2 | 9.7 | 55 | 9.4 | 24.5 | 0.7 | 0.9 | muy_bajo | 1 |
| 2019-07-29 | 0 | 0 | 19.3 | 8.3 | 47 | 11.7 | 32.4 | 0 | 3.7 | muy_bajo | 1 |
| 2019-07-30 | 1 | 7 | 21.1 | 9.6 | 46 | 10.9 | 30.6 | 0 | 6 | bajo | 1 |
| 2019-07-31 | 0 | 0 | 17.3 | 11.4 | 69 | 11.8 | 33.8 | 3.9 | 0.4 | muy_bajo | 0 |
It is generated in your browser from this page’s data: one file per fire, aggregated by day and without individual hotspots.
Live widget for your story
It updates itself while the fire is still active and links to this page. Free, with the attribution shown at the bottom.
Sources for this page: MTBS (USGS/USFS), NASA FIRMS (VIIRS), ERA5 (ECMWF/Copernicus C3S) · Open-Meteo.com (CC BY 4.0), GHSL (JRC). Open-Meteo.com · How we build fire pages: methodology
- Burnt area
- 56,379ha
- official perimeter (MTBS / NIFC)
- Duration
- ≈ 38days
- 23 Jun 2019 – 30 Jul 2019
- Counties hit
- 1
- counties
- Started on
- 23 Jun
- 2019
- Heat detections
- 6,112
- in a single hotspot: 355 MW
- Danger at start
- 1
- Very low · FWI index
- Average daily power
- 3.5GW
- detected power per day, on average
Where it burned
HOTSPOTS BY DAY
23 Jun30 Jul
30 Jul 2019
How it evolved, day by day
23 Jun
28 Jun
8 Jul
16 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
30°high
47km/h · peak gust
29%lowest humidity
It had gone 0 days without rain (1 mm or more) when it started. Rain came after the fire: 3.9 mm on 31 Jul.
This area had burned before
No earlier perimeters overlap this fire since 2016, when the satellite record begins.
How big is it?
London boundary: geoBoundaries · Office for National Statistics (Open Government Licence v3.0).
Paris boundary: geoBoundaries · Institut national de l'information géographique et forestière (IGN-F) (Etalab Open License 2.0).
Madrid boundary: geoBoundaries · Open Data ESRI, IGN Central Registry of Cartography Area (CC BY 4.0).
Berlin boundary: geoBoundaries · Federal Agency for Cartography and Geodesy (dl-de/by-2-0).
This compares size, not location: both shapes are at the same scale, north up, centred on each other.
What happened to each county
-
Yukon-Koyukuk where it started51,777 ha reached on 23 Jun0.1 %
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 2020Built-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)
| Day | High | Min. humidity | Peak gust | Rain | Danger (FWI) |
|---|---|---|---|---|---|
| 23 Jun | 20.4 °C | 43 % | 27 km/h | 0.0 mm | Very low 1 |
| 24 Jun | 21.5 °C | 46 % | 15 km/h | 0.0 mm | Very low 3 |
| 25 Jun | 23.8 °C | 37 % | 13 km/h | 0.0 mm | Low 6 |
| 26 Jun | 22.8 °C | 58 % | 36 km/h | 0.0 mm | Low 8 |
| 27 Jun | 26.5 °C | 31 % | 27 km/h | 0.0 mm | Moderate 12 |
| 28 Jun | 27.6 °C | 35 % | 26 km/h | 0.0 mm | Moderate 13 |
| 29 Jun | 23.7 °C | 54 % | 28 km/h | 0.0 mm | Low 11 |
| 30 Jun | 20.8 °C | 58 % | 47 km/h | 0.8 mm | Low 9 |
| 1 Jul | 16.7 °C | 50 % | 30 km/h | 0.0 mm | Low 8 |
| 2 Jul | 18.9 °C | 65 % | 37 km/h | 1.7 mm | Very low 3 |
| 3 Jul | 18.6 °C | 66 % | 38 km/h | 2.3 mm | Very low 2 |
| 4 Jul | 21.6 °C | 60 % | 21 km/h | 0.0 mm | Very low 3 |
| 5 Jul | 26.6 °C | 38 % | 26 km/h | 0.0 mm | Low 9 |
| 6 Jul | 27.6 °C | 39 % | 26 km/h | 0.0 mm | Moderate 13 |
| 7 Jul | 29.6 °C | 37 % | 28 km/h | 0.0 mm | Moderate 15 |
| 8 Jul | 30.4 °C | 29 % | 36 km/h | 0.0 mm | Moderate 21 |
| 9 Jul | 28.7 °C | 32 % | 18 km/h | 0.0 mm | Moderate 19 |
| 10 Jul | 27.8 °C | 37 % | 32 km/h | 0.1 mm | Moderate 21 |
| 11 Jul | 23.8 °C | 75 % | 32 km/h | 9.2 mm | Very low 0 |
| 12 Jul | 23.2 °C | 51 % | 37 km/h | 3.7 mm | Very low 1 |
| 13 Jul | 20.9 °C | 56 % | 42 km/h | 0.0 mm | Very low 3 |
| 14 Jul | 21.2 °C | 53 % | 17 km/h | 1.3 mm | Very low 2 |
| 15 Jul | 21.0 °C | 63 % | 20 km/h | 8.6 mm | Very low 0 |
| 16 Jul | 21.7 °C | 48 % | 25 km/h | 1.5 mm | Very low 1 |
| 17 Jul | 20.6 °C | 55 % | 34 km/h | 0.0 mm | Very low 3 |
| 18 Jul | 17.1 °C | 62 % | 31 km/h | 0.0 mm | Very low 4 |
| 19 Jul | 15.8 °C | 73 % | 31 km/h | 0.2 mm | Very low 4 |
| 20 Jul | 16.4 °C | 70 % | 35 km/h | 0.2 mm | Very low 5 |
| 21 Jul | 17.7 °C | 63 % | 32 km/h | 0.0 mm | Low 5 |
| 22 Jul | 21.7 °C | 56 % | 17 km/h | 0.0 mm | Low 6 |
| 23 Jul | 25.0 °C | 44 % | 20 km/h | 0.0 mm | Low 9 |
| 24 Jul | 18.7 °C | 62 % | 23 km/h | 5.1 mm | Very low 0 |
| 25 Jul | 16.8 °C | 57 % | 47 km/h | 2.9 mm | Very low 1 |
| 26 Jul | 14.9 °C | 58 % | 33 km/h | 5.9 mm | Very low 0 |
| 27 Jul | 15.7 °C | 57 % | 21 km/h | 0.6 mm | Very low 0 |
| 28 Jul | 18.2 °C | 55 % | 24 km/h | 0.7 mm | Very low 1 |
| 29 Jul | 19.3 °C | 47 % | 32 km/h | 0.0 mm | Very low 4 |
| 30 Jul | 21.1 °C | 46 % | 31 km/h | 0.0 mm | Low 6 |
| 31 Jul after | 17.3 °C | 69 % | 34 km/h | 3.9 mm | Very low 0 |
Its twins: fires that started in the same weather
It started with an FWI of 1.0, a minimum humidity of 43% and rain the day before. Fires in the area that started in weather like this since 2016: 27.
FWI at the start
1.0
Minimum humidity
43 %
Days without rain
0
this fire
chosen twins
rest of the area
Almost identicalSimilar
Outlines of the closest twins
This fire · Hurst Creek Fire, June 2019
56,379 ha
38 days
FWI 1.0
Min. humidity 43 %
Pitka Fork Fire, June 2017
6,816 ha
3 days
FWI 2.2
Min. humidity 42 %
174 km away, in 2017
First rain (1 mm or more) after it ended: 3.5 mm on 9 Jun.
Titnuk Creek Fire, June 2020
2,265 ha
5 days
FWI 2.7
Min. humidity 41 %
243 km away, in 2020
First rain (1 mm or more) after it ended: 7.7 mm on 19 Jun.
Hook Creek Fire, June 2022
1,925 ha
7 days
FWI 3.4
Min. humidity 43 %
228 km away, in 2022
First rain (1 mm or more) after it ended: 8.5 mm on 13 Jun.
Owhat River 2 Fire, July 2016
492 ha
4 days
FWI 7.3
Min. humidity 43 %
171 km away, in 2016
First rain (1 mm or more) after it ended: 1.2 mm on 19 Jul.
Wapoo Creek 2 Fire, June 2020
707 ha
3 days
FWI 2.5
Min. humidity 37 %
101 km away, in 2020
First rain (1 mm or more) after it ended: 2.9 mm on 6 Jun.
What happened to them
- 7 days
- median duration
- 1,925 ha
- median area
- 78 %
- went past 1,000 ha
- 6.1 mm
- rain at the end (median; 27 of 27 had it)
It was 29.3 times larger than the median of its twins and lasted 38 days, against 7 days.
None of its 27 twins burned more. The weather on the first day does not explain everything: the wind in the following days, the fuel and the firefighting also count. All of them had rain in the ten days after the end: the first rainy day brought a median of 6.1 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
3.9 mmfirst rain
31 Julthe day after it ended
47km/h · max. gust
It was considered over on 30 Jul, and on 31 Jul 3.9 mm fell. We do not know whether the rain or the firefighters put it out. Twins with rain when they ended: 27 of 27, with a median of 6.1 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.
Before and after, from space
Drag the line to compare the same ground before the fire and after it.
↔
Before · 16 Jun 2019
After · 6 Aug 2019
Sentinel-2 did not pass over on that day. Try another date, or use false colour, which is daily.
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 · 6,112Every 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
Frequently asked questions
- How long did the Hurst Creek Fire last?
- The official perimeter only gives the start date (23 June 2019). The end comes from the heat detections inside the perimeter: it burned until 30 July 2019 (38 days from 23 June 2019), 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 56,379 hectares (563.8 km²). Other tallies, such as daily incident reports, may give slightly different figures.
- Which counties burned?
- The fire only entered Yukon-Koyukuk (51,777 ha, 0.1 %).
- What was the weather like?
- During the fire the temperature reached 30.4 °C, humidity dropped to 29 % and gusts hit 47 km/h. The fire danger index (FWI) reached 21, 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: 27. Their median duration was 7 days and their median area 1,925 ha; 78 % went past 1,000 ha. None of its 27 twins burned more. The weather on the first day does not explain everything: the wind in the following days, the fuel and the firefighting also count. All of them had rain in the ten days after the end: the first rainy day brought a median of 6.1 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
- NIFC · National Interagency Fire Center ↗
- InciWeb · Incident Information System ↗
- MTBS · Monitoring Trends in Burn Severity ↗
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
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. 6,112 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.
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.