How long did the Mackenzie County fire last?

According to the heat detections seen by satellite inside the perimeter, it burned from 17 September 2023 to 23 September 2023 (7 days). The perimeter dates it from 19 September 2023 to 23 September 2023.

How much area did it burn?

The official perimeter mapped by Canada’s CWFIS (Natural Resources Canada) is 4,794 hectares (47.9 km²). Other tallies, such as those of provincial agencies, may give slightly different figures.

Which census subdivisions burned?

The fire only entered Mackenzie County (4,956 ha, 0.1 %).

What was the weather like?

During the fire the temperature reached 23.9 °C, humidity dropped to 31 % and gusts hit 44 km/h. The fire danger index (FWI) reached 22, class 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.

CA · Canada · 2023-09-17 → 2023-09-23

Mackenzie County fire, September 2023 Mackenzie County

Out · last detection 23 Sept 2023, 20:21 UTC

The fire started on 17 September 2023 in Mackenzie County, Canada, and satellites saw it burning for 7 days. Canada’s CWFIS (Natural Resources Canada) mapped an official burnt perimeter of 4,794 hectares from satellite imagery, spread across a single census subdivision.

It is the 108th largest in Alberta since 2016 (of 243 with a page). Number 276 in Canada in 2023, of 489.

Compare with…

Suggestions: Mackenzie County · 2024 Mackenzie County · 2022 Mackenzie County · 2018 Mackenzie County · 2025

Burnt area: 4,794ha; official perimeter (CWFIS)
Duration: 7days; 17 Sept 2023 – 23 Sept 2023
Census subdivisions hit: 1; municipalities
Started on: 17 Sept; 2023
Heat detections: 549; in a single hotspot: 152 MW
Danger at start: 14; Moderate · FWI index
Average daily power: 396MW; detected power per day, on average

HOTSPOTS BY DAY 17 Sept23 Sept

Play back 23 Sept 2023

How it evolved, day by day

17 Sept 18 Sept 19 Sept 20 Sept 21 Sept 22 Sept 23 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

24°high

44km/h · peak gust

31%lowest humidity

It had gone 5 days without rain (1 mm or more) when it started. Rain came after the fire: 16.0 mm on 24 Sept.

This area had burned before

No earlier perimeters overlap this fire since 2016, when the satellite record begins.

How big is it?

It burned the equivalent of 3% of the area of London (48 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

Mackenzie County where it started

4,956 ha reached on 17 Sept

0.1 %

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)

Day	High	Min. humidity	Peak gust	Rain	Danger (FWI)
19 Sept	16.2 °C	45 %	26 km/h	0.2 mm	Moderate 14
20 Sept	16.0 °C	37 %	34 km/h	0.0 mm	Moderate 15
21 Sept	21.4 °C	34 %	36 km/h	0.0 mm	Moderate 17
22 Sept	23.9 °C	31 %	44 km/h	0.0 mm	High 22
23 Sept	16.6 °C	42 %	32 km/h	0.0 mm	Moderate 18
24 Sept after	9.0 °C	74 %	27 km/h	16.0 mm	Very low 0

Before and after, from space

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

↔

Before · 10 Sept 2023

After · 30 Sept 2023

Before After

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 25 September 2023 the air beside the fire reached 338 µg/m³ of PM2.5. That day averaged 138: 9.2 times the WHO daily guideline (15).

PM2.5 peak338 µg/m³

Days over the guideline9 days

PM10484 µg/m³

Optical depth8.25

WHO 15

17181920212223242526

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 time	Satellite	FRP (MW)	Lat	Lon

Other fires nearby

All fires in Canada ›

Frequently asked questions

How long did the Mackenzie County fire last?: According to the heat detections seen by satellite inside the perimeter, it burned from 17 September 2023 to 23 September 2023 (7 days). The perimeter dates it from 19 September 2023 to 23 September 2023.
How much area did it burn?: The official perimeter mapped by Canada’s CWFIS (Natural Resources Canada) is 4,794 hectares (47.9 km²). Other tallies, such as those of provincial agencies, may give slightly different figures.
Which census subdivisions burned?: The fire only entered Mackenzie County (4,956 ha, 0.1 %).
What was the weather like?: During the fire the temperature reached 23.9 °C, humidity dropped to 31 % and gusts hit 44 km/h. The fire danger index (FWI) reached 22, class 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.

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

NASA FIRMS ↗
CWFIS · Interactive map ↗

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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What do you think is wrong?

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What really happened?

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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: NBAC (Natural Resources Canada), official.
Dates adjusted with the VIIRS detections inside the perimeter, which said 19 September 2023 to 23 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.

Where it burned