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Fraser Valley A fire, July 2023 Fraser Valley A, Thompson-Nicola I (Blue Sky C*, Inkahtsaph 6

Out · last detection 17 Sept 2023, 10:43 UTC

The fire started on 8 July 2023 in Fraser Valley A, Canada, and satellites saw it burning for 72 days. Canada’s CWFIS (Natural Resources Canada) mapped an official burnt perimeter of 12,232 hectares from satellite imagery, spread across 4 census subdivisions.

It is the 89th largest in British Columbia since 2016 (of 449 with a page). Number 147 in Canada in 2023, of 489.

Compare with…

Suggestions: Thompson-Nicola I (Blue Sky C* · 2021Fraser Valley A · 2026Fraser Valley A · 2026Thompson-Nicola N (Beautiful * · 2026

Burnt area
12,232ha
official perimeter (CWFIS)
Duration
72days
8 Jul 2023 – 17 Sept 2023
Census subdivisions hit
4
municipalities
Started on
8 Jul
2023
Heat detections
2,579
in a single hotspot: 504 MW
Danger at start
5
Very low · FWI index
Average daily power
806MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 8 Jul17 Sept
17 Sept 2023

How it evolved, day by day

9 Jul 2023 · 19 MW · 10 10 Jul 2023 · 47 MW · 13 11 Jul 2023 · 5 MW · 1 12 Jul 2023 · 94 MW · 6 13 Jul 2023 · 25 MW · 13 14 Jul 2023 · 10 MW · 5 15 Jul 2023 · 201 MW · 37 16 Jul 2023 · 889 MW · 63 17 Jul 2023 · 40 MW · 12 19 Jul 2023 · 0 MW · 1 20 Jul 2023 · 21 MW · 7 21 Jul 2023 · 63 MW · 20 22 Jul 2023 · 4 MW · 2 23 Jul 2023 · 9 MW · 6 1 Aug 2023 · 0 MW · 1 17 Aug 2023 · 2,515 MW · 23 18 Aug 2023 · 5,083 MW · 381 19 Aug 2023 · 8,816 MW · 296 20 Aug 2023 · 1,251 MW · 345 21 Aug 2023 · 608 MW · 136 22 Aug 2023 · 1,891 MW · 209 23 Aug 2023 · 1,155 MW · 190 24 Aug 2023 · 65 MW · 11 25 Aug 2023 · 44 MW · 30 26 Aug 2023 · 185 MW · 52 27 Aug 2023 · 845 MW · 134 28 Aug 2023 · 1,276 MW · 179 29 Aug 2023 · 451 MW · 171 9 Sept 2023 · 31 MW · 1 10 Sept 2023 · 57 MW · 7 11 Sept 2023 · 3 MW · 3 14 Sept 2023 · 3 MW · 1 15 Sept 2023 · 1,794 MW · 46 16 Sept 2023 · 617 MW · 138 17 Sept 2023 · 79 MW · 29
9 Jul 14 Jul 20 Jul 17 Aug 19 Aug 22 Aug 27 Aug 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
63km/h · peak gust
24%lowest humidity

It had gone 0 days without rain (1 mm or more) when it started. Rain came after the fire: 5.4 mm on 18 Sept.

This area had burned before

0% of the perimeter overlaps earlier fires recorded since 2016: 13 ha in 2021.

How big is it?

10 km
It burned the equivalent of 7.7% of the area of London (122 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. Fraser Valley A where it started
    8,649 ha reached on 9 Jul
    3.7 %
  2. Thompson-Nicola I (Blue Sky C*
    3,554 ha reached on 18 Aug
    0.6 %
  3. Inkahtsaph 6
    16 ha reached on 18 Aug
    8.0 %
  4. Siska Flat
    4 ha
    6.2 %

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 area0.29 ha
Residents< 20

Inside the perimeter there were about 0.29 hectares of 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)
8 Jul 25.3 °C 36 % 30 km/h 1.9 mm Very low 5
9 Jul 25.8 °C 28 % 47 km/h 0.0 mm Moderate 14
10 Jul 20.3 °C 46 % 38 km/h 0.3 mm Moderate 13
11 Jul 20.7 °C 48 % 35 km/h 0.0 mm Moderate 12
12 Jul 20.6 °C 48 % 36 km/h 1.0 mm Low 7
13 Jul 20.1 °C 54 % 30 km/h 1.5 mm Very low 4
14 Jul 23.2 °C 40 % 35 km/h 0.0 mm Low 10
15 Jul 24.0 °C 36 % 48 km/h 0.2 mm Moderate 15
16 Jul 23.7 °C 35 % 59 km/h 0.0 mm Moderate 18
17 Jul 14.9 °C 56 % 60 km/h 1.9 mm Very low 4
18 Jul 21.9 °C 36 % 26 km/h 0.0 mm Low 8
19 Jul 26.2 °C 29 % 30 km/h 0.0 mm Moderate 15
20 Jul 26.8 °C 28 % 47 km/h 0.6 mm Moderate 20
21 Jul 24.6 °C 37 % 48 km/h 0.0 mm High 22
22 Jul 20.9 °C 42 % 62 km/h 0.0 mm Moderate 21
23 Jul 22.3 °C 38 % 49 km/h 0.0 mm Moderate 20
24 Jul 15.0 °C 63 % 55 km/h 5.4 mm Very low 1
25 Jul 12.5 °C 72 % 52 km/h 2.9 mm Very low 0
26 Jul 17.7 °C 43 % 23 km/h 0.0 mm Very low 2
27 Jul 21.3 °C 41 % 24 km/h 1.8 mm Very low 2
28 Jul 22.5 °C 35 % 27 km/h 0.7 mm Low 6
29 Jul 20.9 °C 46 % 47 km/h 0.4 mm Low 10
30 Jul 19.8 °C 39 % 53 km/h 0.0 mm Moderate 13
31 Jul 21.2 °C 33 % 45 km/h 0.0 mm Moderate 15
1 Aug 21.5 °C 31 % 44 km/h 0.0 mm Moderate 17
2 Aug 20.9 °C 37 % 51 km/h 0.0 mm Moderate 18
3 Aug 24.0 °C 29 % 36 km/h 0.0 mm Moderate 19
4 Aug 25.9 °C 25 % 20 km/h 0.0 mm Moderate 19
5 Aug 26.5 °C 26 % 26 km/h 0.0 mm Moderate 20
6 Aug 24.6 °C 41 % 35 km/h 0.8 mm Moderate 14
7 Aug 21.8 °C 51 % 34 km/h 3.2 mm Very low 3
8 Aug 17.5 °C 68 % 38 km/h 1.4 mm Very low 3
9 Aug 14.3 °C 81 % 45 km/h 3.6 mm Very low 0
10 Aug 16.6 °C 61 % 34 km/h 0.9 mm Very low 1
11 Aug 20.1 °C 45 % 44 km/h 0.0 mm Very low 4
12 Aug 23.5 °C 42 % 23 km/h 0.1 mm Low 8
13 Aug 28.4 °C 31 % 23 km/h 0.0 mm Moderate 15
14 Aug 30.1 °C 28 % 22 km/h 0.0 mm Moderate 18
15 Aug 29.5 °C 32 % 48 km/h 0.0 mm High 23
16 Aug 29.3 °C 35 % 21 km/h 0.0 mm Moderate 20
17 Aug 25.6 °C 39 % 61 km/h 0.0 mm High 23
18 Aug 18.2 °C 39 % 45 km/h 3.6 mm Very low 3
19 Aug 17.8 °C 33 % 37 km/h 0.0 mm Low 7
20 Aug 19.4 °C 32 % 25 km/h 0.0 mm Moderate 11
21 Aug 22.0 °C 31 % 39 km/h 0.0 mm Moderate 15
22 Aug 16.8 °C 45 % 48 km/h 0.3 mm Moderate 16
23 Aug 12.4 °C 57 % 42 km/h 0.6 mm Moderate 12
24 Aug 17.5 °C 45 % 37 km/h 0.0 mm Moderate 12
25 Aug 20.7 °C 38 % 21 km/h 0.1 mm Moderate 14
26 Aug 24.7 °C 28 % 25 km/h 0.0 mm Moderate 18
27 Aug 27.4 °C 24 % 24 km/h 0.0 mm Moderate 21
28 Aug 27.1 °C 27 % 26 km/h 0.0 mm High 23
29 Aug 18.2 °C 65 % 27 km/h 9.3 mm Very low 0
30 Aug 14.8 °C 69 % 35 km/h 6.8 mm Very low 0
31 Aug 12.7 °C 85 % 35 km/h 15.0 mm Very low 0
1 Sept 19.8 °C 47 % 34 km/h 0.0 mm Very low 0
2 Sept 24.1 °C 40 % 36 km/h 0.0 mm Very low 1
3 Sept 16.0 °C 66 % 44 km/h 0.0 mm Very low 2
4 Sept 15.2 °C 63 % 34 km/h 1.8 mm Very low 1
5 Sept 14.5 °C 54 % 40 km/h 0.3 mm Very low 2
6 Sept 14.8 °C 50 % 42 km/h 0.4 mm Very low 3
7 Sept 17.1 °C 42 % 23 km/h 0.0 mm Very low 5
8 Sept 19.2 °C 36 % 22 km/h 0.0 mm Low 7
9 Sept 22.3 °C 29 % 24 km/h 0.0 mm Low 9
10 Sept 22.7 °C 33 % 54 km/h 0.0 mm Moderate 13
11 Sept 15.7 °C 69 % 40 km/h 0.5 mm Low 7
12 Sept 13.3 °C 71 % 37 km/h 1.1 mm Very low 2
13 Sept 17.6 °C 46 % 24 km/h 0.0 mm Very low 4
14 Sept 21.6 °C 32 % 20 km/h 0.0 mm Low 8
15 Sept 22.1 °C 28 % 50 km/h 0.0 mm Moderate 14
16 Sept 21.0 °C 31 % 55 km/h 0.0 mm Moderate 15
17 Sept 15.1 °C 50 % 63 km/h 0.0 mm Moderate 13
18 Sept after 10.5 °C 69 % 54 km/h 5.4 mm Very low 0

Before and after, from space

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

Before · 1 Jul 2023
After · 24 Sept 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 21 August 2023 the air beside the fire reached 277 µg/m³ of PM2.5. That day averaged 173: 12 times the WHO daily guideline (15).

PM2.5 peak277 µg/m³
Days over the guideline19 days
PM10396 µg/m³
Optical depth2.58
678910111213141516171819202122232425262728293031123456789101112131415161718192021222324252627282930311234567891011121314151617181920
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 · 2,579Every 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 Fraser Valley A fire last?
It burned between 8 July 2023 and 17 September 2023: 72 days, according to the dates recorded by Canada’s CWFIS and the heat detections seen by satellite.
How much area did it burn?
The official perimeter mapped by Canada’s CWFIS (Natural Resources Canada) is 12,232 hectares (122.3 km²). Other tallies, such as those of provincial agencies, may give slightly different figures.
Which census subdivisions burned?
The fire entered 4 census subdivisions: Fraser Valley A (8,649 ha, 3.7 %); Thompson-Nicola I (Blue Sky C* (3,554 ha, 0.6 %); Inkahtsaph 6 (16 ha, 8.0 %); Siska Flat (4 ha, 6.2 %).
What was the weather like?
During the fire the temperature reached 30.1 °C, humidity dropped to 24 % and gusts hit 63 km/h. The fire danger index (FWI) reached 23, 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

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.

Report an error
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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 from the perimeter: the VIIRS detections inside it did not change them. 2,579 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.