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CA · Canada · –

Wood Buffalo fire, 27 May 2023 Wood Buffalo

Out · last detection 25 Sept 2023, 09:51 UTC

The fire started on 27 May 2023 in Wood Buffalo, Canada, and satellites saw it burning for 122 days. Canada’s CWFIS (Natural Resources Canada) mapped an official burnt perimeter of 12,089 hectares from satellite imagery, spread across a single census subdivision.

It is the 54th largest in Alberta since 2016 (of 176 with a page). Number 149 in Canada in 2023, of 489.

Burnt area
12,089ha
official perimeter (CWFIS)
Duration
122days
27 May 2023 – 25 Sept 2023
Census subdivisions hit
1
municipalities
Started on
27 May
2023
Heat detections
549
in a single hotspot: 316 MW
Danger at start
34
High · FWI index
Average daily power
1,000MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 27 May25 Sept
25 Sept 2023

How it evolved, day by day

28 May 2023 · 2,193 MW · 81 29 May 2023 · 5,708 MW · 156 30 May 2023 · 993 MW · 84 31 May 2023 · 391 MW · 46 1 Jun 2023 · 15 MW · 1 2 Jun 2023 · 679 MW · 21 3 Jun 2023 · 2,339 MW · 81 4 Jun 2023 · 11 MW · 9 10 Jun 2023 · 2,570 MW · 44 11 Jun 2023 · 4 MW · 1 30 Aug 2023 · 8 MW · 1 1 Sept 2023 · 20 MW · 2 2 Sept 2023 · 19 MW · 8 23 Sept 2023 · 41 MW · 12 25 Sept 2023 · 4 MW · 2
29 May 3 Jun 11 Jun 2 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

28°high
73km/h · peak gust
20%lowest humidity

It had gone 2 days without rain (1 mm or more) when it started. Rain came after the fire: 1.1 mm on 26 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 7.6% of the area of London (121 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 census subdivision

  1. Wood Buffalo where it started
    12,075 ha reached on 28 May
    0.2 %

Burnt area inside each census subdivision, 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 2025
Built-up area< 0.1 ha
Residents< 20

Inside the perimeter there was no noticeable built-up land and almost nobody lived there (GHSL 2025, 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. The GHSL 2025 epoch is a projection made from 2020 and earlier data.

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 Strong wind: 15 % of the area in Canada

Day High Min. humidity Peak gust Rain Danger (FWI)
27 May 25.7 °C 25 % 50 km/h 0.7 mm High 34
28 May 23.2 °C 22 % 48 km/h 0.0 mm High 36
29 May 20.8 °C 26 % 54 km/h 0.2 mm Very high 39
30 May 21.2 °C 20 % 36 km/h 0.0 mm High 29
31 May 22.2 °C 28 % 23 km/h 0.1 mm Moderate 21
1 Jun 19.6 °C 29 % 33 km/h 0.2 mm High 26
2 Jun 21.9 °C 30 % 27 km/h 0.0 mm High 24
3 Jun 24.7 °C 27 % 33 km/h 0.0 mm High 28
4 Jun 21.1 °C 69 % 33 km/h 3.6 mm Very low 5
5 Jun 20.5 °C 56 % 37 km/h 8.7 mm Very low 2
6 Jun 19.3 °C 32 % 48 km/h 0.3 mm Very low 4
7 Jun 20.6 °C 31 % 56 km/h 0.0 mm Moderate 19
8 Jun 21.1 °C 37 % 25 km/h 0.0 mm Moderate 12
9 Jun 25.1 °C 32 % 32 km/h 0.0 mm Moderate 18
10 Jun 27.7 °C 29 % 61 km/h 0.0 mm High 31
11 Jun 24.0 °C 26 % 48 km/h 2.3 mm Moderate 14
12 Jun 19.1 °C 38 % 31 km/h 0.3 mm Moderate 14
13 Jun 20.0 °C 54 % 37 km/h 19.8 mm Very low 3
14 Jun 10.3 °C 96 % 44 km/h 25.1 mm Very low 0
15 Jun 17.2 °C 44 % 45 km/h 1.7 mm Very low 0
16 Jun 17.4 °C 50 % 42 km/h 7.1 mm Very low 1
17 Jun 16.1 °C 58 % 51 km/h 9.1 mm Very low 0
18 Jun 16.2 °C 57 % 41 km/h 0.7 mm Very low 0
19 Jun 16.5 °C 42 % 73 km/h 3.4 mm Low 6
20 Jun 15.8 °C 35 % 46 km/h 0.0 mm Very low 1
21 Jun 19.0 °C 29 % 35 km/h 0.0 mm Low 5
22 Jun 19.4 °C 48 % 30 km/h 2.6 mm Very low 1
23 Jun 25.9 °C 24 % 23 km/h 0.0 mm Very low 4
24 Jun 25.4 °C 35 % 42 km/h 3.9 mm Moderate 15
25 Jun 21.9 °C 32 % 24 km/h 0.2 mm Very low 1
26 Jun 21.9 °C 57 % 36 km/h 4.8 mm Very low 3
27 Jun 25.3 °C 38 % 24 km/h 0.0 mm Very low 1
28 Jun 27.9 °C 35 % 28 km/h 2.2 mm Low 8
29 Jun 25.1 °C 48 % 37 km/h 5.4 mm Low 6
30 Jun 25.9 °C 29 % 46 km/h 0.7 mm Very low 3
1 Jul 21.7 °C 30 % 31 km/h 1.8 mm Low 7
2 Jul 14.6 °C 76 % 49 km/h 22.5 mm Very low 0
3 Jul 18.3 °C 43 % 53 km/h 5.7 mm Very low 0
4 Jul 21.8 °C 30 % 23 km/h 0.0 mm Very low 1
5 Jul 25.0 °C 35 % 45 km/h 1.5 mm Low 11
6 Jul 20.6 °C 37 % 31 km/h 0.0 mm Very low 5
7 Jul 23.9 °C 34 % 30 km/h 0.0 mm Low 11
8 Jul 26.3 °C 41 % 37 km/h 0.0 mm Moderate 16
9 Jul 22.9 °C 38 % 32 km/h 0.0 mm Moderate 14
10 Jul 20.6 °C 35 % 40 km/h 0.0 mm Moderate 18
11 Jul 25.7 °C 34 % 26 km/h 0.0 mm Moderate 14
12 Jul 25.8 °C 27 % 35 km/h 0.0 mm Moderate 19
13 Jul 23.0 °C 36 % 47 km/h 0.0 mm High 27
14 Jul 21.8 °C 38 % 40 km/h 0.4 mm High 23
15 Jul 21.9 °C 41 % 36 km/h 0.0 mm Moderate 16
16 Jul 23.2 °C 39 % 34 km/h 0.2 mm Moderate 18
17 Jul 17.0 °C 64 % 46 km/h 7.1 mm Low 5
18 Jul 20.1 °C 60 % 21 km/h 1.8 mm Very low 0
19 Jul 21.9 °C 59 % 23 km/h 1.2 mm Very low 1
20 Jul 23.7 °C 48 % 23 km/h 1.1 mm Very low 2
21 Jul 25.8 °C 37 % 26 km/h 0.0 mm Low 9
22 Jul 25.2 °C 41 % 25 km/h 0.4 mm Moderate 12
23 Jul 25.1 °C 42 % 26 km/h 5.4 mm Moderate 13
24 Jul 24.6 °C 45 % 28 km/h 0.5 mm Very low 3
25 Jul 17.9 °C 63 % 44 km/h 37.8 mm Very low 0
26 Jul 17.5 °C 56 % 31 km/h 1.0 mm Very low 0
27 Jul 19.1 °C 44 % 27 km/h 0.2 mm Very low 1
28 Jul 21.6 °C 35 % 16 km/h 0.0 mm Very low 3
29 Jul 24.3 °C 34 % 29 km/h 0.0 mm Low 10
30 Jul 25.8 °C 38 % 38 km/h 0.0 mm Moderate 12
31 Jul 18.4 °C 76 % 27 km/h 11.9 mm Very low 0
1 Aug 17.7 °C 72 % 31 km/h 11.6 mm Very low 0
2 Aug 19.2 °C 62 % 21 km/h 0.7 mm Very low 0
3 Aug 16.4 °C 82 % 25 km/h 12.1 mm Very low 0
4 Aug 21.6 °C 55 % 37 km/h 0.3 mm Very low 0
5 Aug 22.6 °C 49 % 34 km/h 0.2 mm Very low 1
6 Aug 20.2 °C 60 % 30 km/h 3.2 mm Very low 0
7 Aug 20.0 °C 37 % 29 km/h 0.0 mm Very low 2
8 Aug 19.4 °C 41 % 37 km/h 0.0 mm Very low 5
9 Aug 13.2 °C 70 % 42 km/h 12.4 mm Very low 0
10 Aug 13.9 °C 87 % 29 km/h 6.8 mm Very low 0
11 Aug 17.2 °C 60 % 25 km/h 3.1 mm Very low 0
12 Aug 20.2 °C 55 % 37 km/h 1.7 mm Very low 0
13 Aug 26.8 °C 41 % 40 km/h 0.0 mm Very low 2
14 Aug 20.7 °C 35 % 51 km/h 0.2 mm Low 7
15 Aug 16.8 °C 66 % 28 km/h 5.4 mm Very low 0
16 Aug 20.1 °C 41 % 37 km/h 1.1 mm Very low 0
17 Aug 21.0 °C 45 % 35 km/h 0.0 mm Very low 3
18 Aug 12.0 °C 66 % 36 km/h 0.6 mm Very low 3
19 Aug 18.9 °C 46 % 36 km/h 0.9 mm Very low 3
20 Aug 22.3 °C 35 % 24 km/h 0.1 mm Low 6
21 Aug 24.0 °C 28 % 21 km/h 0.0 mm Low 10
22 Aug 23.4 °C 31 % 19 km/h 0.0 mm Low 10
23 Aug 18.3 °C 56 % 20 km/h 0.2 mm Low 8
24 Aug 19.2 °C 40 % 30 km/h 0.0 mm Moderate 12
25 Aug 23.4 °C 36 % 35 km/h 0.0 mm Moderate 14
26 Aug 23.8 °C 47 % 38 km/h 0.0 mm Moderate 15
27 Aug 24.2 °C 45 % 30 km/h 0.0 mm Moderate 13
28 Aug 27.2 °C 42 % 25 km/h 0.0 mm Moderate 13
29 Aug 28.2 °C 36 % 23 km/h 0.0 mm Moderate 14
30 Aug 26.7 °C 42 % 19 km/h 0.6 mm Moderate 13
31 Aug 23.2 °C 57 % 30 km/h 2.4 mm Low 10
1 Sept 23.2 °C 34 % 60 km/h 0.0 mm Moderate 12
2 Sept 18.3 °C 42 % 57 km/h 0.5 mm Moderate 18
3 Sept 16.3 °C 39 % 42 km/h 0.0 mm Moderate 15
4 Sept 12.5 °C 39 % 38 km/h 2.5 mm Very low 4
5 Sept 14.9 °C 35 % 34 km/h 0.1 mm Low 7
6 Sept 11.2 °C 76 % 23 km/h 7.2 mm Very low 0
7 Sept 16.8 °C 50 % 34 km/h 0.7 mm Very low 0
8 Sept 18.9 °C 36 % 23 km/h 0.0 mm Very low 2
9 Sept 20.9 °C 28 % 16 km/h 0.0 mm Low 5
10 Sept 22.4 °C 35 % 36 km/h 0.0 mm Moderate 15
11 Sept 24.5 °C 34 % 47 km/h 0.0 mm Moderate 21
12 Sept 19.2 °C 45 % 27 km/h 0.0 mm Moderate 15
13 Sept 18.0 °C 47 % 47 km/h 1.8 mm Moderate 18
14 Sept 16.3 °C 46 % 42 km/h 3.1 mm Very low 3
15 Sept 23.0 °C 29 % 46 km/h 0.0 mm Low 10
16 Sept 18.8 °C 38 % 35 km/h 0.0 mm Moderate 12
17 Sept 19.5 °C 42 % 31 km/h 0.0 mm Moderate 12
18 Sept 14.1 °C 47 % 44 km/h 0.4 mm Moderate 15
19 Sept 16.2 °C 40 % 27 km/h 0.1 mm Moderate 12
20 Sept 15.5 °C 49 % 19 km/h 0.0 mm Low 10
21 Sept 18.9 °C 33 % 54 km/h 0.0 mm High 24
22 Sept 23.9 °C 28 % 44 km/h 0.0 mm High 22
23 Sept 21.7 °C 48 % 53 km/h 0.0 mm High 23
24 Sept 16.8 °C 50 % 44 km/h 0.0 mm Moderate 12
25 Sept 15.8 °C 47 % 46 km/h 0.0 mm Low 10
26 Sept after 19.8 °C 43 % 48 km/h 1.1 mm Moderate 13

Its twins: fires that started in the same weather

It started with an FWI of 34.2, a minimum humidity of 25% and 2 days without rain. Fires in the area that started in weather like this since 2016: 17.

FWI at the start 34.2
Minimum humidity 25 %
Days without rain 2
this fire chosen twins rest of the area
Almost identicalSimilar

Outlines of the closest twins

Wood Buffalo fire, July 2024
15,819 ha 37 days FWI 32.1 Min. humidity 26 % 164 km away, in 2024

First rain (1 mm or more) after it ended: 3.7 mm on 17 Aug.

What happened to them

22 days
median duration
6,464 ha
median area
35 %
went past 10,000 ha
3.3 mm
rain at the end (median; 17 of 17 had it)

It was 1.9 times larger than the median of its twins and lasted 122 days, against 22 days.

Only 5 of its 17 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 3.3 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

1.1 mmfirst rain
26 Septthe day after it ended
73km/h · max. gust

It was considered over on 25 Sept, and on 26 Sept 1.1 mm fell. We do not know whether the rain or the firefighters put it out. Twins with rain when they ended: 17 of 17, with a median of 3.3 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 · 20 May 2023
After · 2 Oct 2023

If the day is cloudy, change the date: each satellite passes once a day. In false colour the burnt ground looks brown or red.

The smoke

CAMS · Copernicus

On 15 July 2023 the air beside the fire reached 417 µg/m³ of PM2.5. That day averaged 255: 17 times the WHO daily guideline (15).

PM2.5 peak417 µg/m³
Days over the guideline80 days
PM10596 µg/m³
Optical depth8.88
25 May19 Jun14 Jul8 Aug2 Sept
Good Fair Moderate Poor Very poor Extremely poor

Particles from the Copernicus CAMS model at the centre of the perimeter; these are not measurements in each town. The pale bar is the worst hour, the solid one the daily average.

Open-Meteo.com (CC BY 4.0) · Copernicus Atmosphere Monitoring Service (CAMS)

Detections table · 549Every 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 Canada

Frequently asked questions

How long did the Wood Buffalo fire last?
According to the heat detections seen by satellite inside the perimeter, it burned from 27 May 2023 to 25 September 2023 (122 days). The perimeter dates it from 27 May 2023 to 22 September 2023.
How much area did it burn?
The official perimeter mapped by Canada’s CWFIS (Natural Resources Canada) is 12,089 hectares (120.9 km²). Other tallies, such as those of provincial agencies, may give slightly different figures.
Which census subdivisions burned?
The fire only entered Wood Buffalo (12,075 ha, 0.2 %).
What was the weather like?
During the fire the temperature reached 28.2 °C, humidity dropped to 20 % and gusts hit 73 km/h. The fire danger index (FWI) reached 39, class Very high.
Where does this data come from?
From the official burnt perimeter of Canada’s CWFIS (NBAC, Natural Resources Canada) or, for the current season and until NBAC publishes it, the one rebuilt by GWIS (Copernicus); from NASA FIRMS VIIRS hotspots; and from the administrative boundaries of Canada. 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 22 days and their median area 6,464 ha; 35 % went past 10,000 ha. Only 5 of its 17 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 3.3 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 · 1 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.
  1. Last day with fire: 22 September 2023 → 25 September 2023.

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: NBAC (Natural Resources Canada), official.
  • Dates adjusted with the VIIRS detections inside the perimeter, which said 27 May 2023 to 22 September 2023. 549 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 2025, 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: it comes from the National Burned Area Composite (NBAC) of the Canadian Wildland Fire Information System (CWFIS), Natural Resources Canada, which maps it on satellite imagery and publishes it under the Open Government Licence – Canada. Until NBAC publishes the current season, this year’s fires carry the perimeter rebuilt from heat detections by GWIS (Copernicus, CC BY 4.0), which is approximate. Heat detections come from the VIIRS sensors aboard Suomi-NPP and NOAA-20, distributed by NASA FIRMS at 375 m resolution. Census subdivision boundaries come from geoBoundaries ADM3 (Open Data Commons Open Database License 1.0). The area per census subdivision is computed by WorldFires by crossing the perimeter with those boundaries, so it may differ slightly from official figures.