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Gray Fire, August 2023 Spokane

Out · last detection 19 Aug 2023, 21:14 UTC

The fire started on 18 August 2023 in Spokane, United States, and satellites saw it burning for 1 day. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 4,083 hectares, spread across a single county.

It is the 76th largest in Washington since 2016 (of 285 with a page). Number 41 in United States in 2023, of 305.

Burnt area
4,083ha
official perimeter (MTBS / NIFC)
Duration
1day
18 Aug 2023 – 18 Aug 2023
Municipalities hit
1
counties
Started on
18 Aug
2023
Heat detections
265
in a single hotspot: 226 MW
Danger at start
73
Very extreme · FWI index
Energy released
5.8GW
sum of detected power

Where it burned

19 Aug 2023
HOTSPOTS BY DAY 18 Aug18 Aug

How it evolved, day by day

1819

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

The weather it burned in

31°high
61km/h · peak gust
10%lowest humidity

It had gone 10 days without rain (1 mm or more) when it started. Rain came after the fire: 1.5 mm on 22 Aug.

This area had burned before

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

What happened to each town

  1. Spokane where it started
    4,068 ha reached on 18 Aug
    0.9 %

Burnt area inside each county, from crossing the official perimeter with administrative boundaries. The distance is from the town centre to the nearest fire: staying a kilometre away does not mean it reached the houses.

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 Aug 31.4 °C 10 % 61 km/h 0.0 mm Very extreme 73
19 Aug after 26.8 °C 16 % 31 km/h 0.0 mm Very high 49
20 Aug after 27.1 °C 19 % 35 km/h 0.0 mm Very high 46
21 Aug after 25.1 °C 35 % 33 km/h 0.3 mm High 35
22 Aug after 19.3 °C 47 % 43 km/h 1.5 mm Moderate 16

Before and after, from space

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

Before · 11 Aug 2023
After · 25 Aug 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 20 August 2023 the air beside the fire reached 174 µg/m³ of PM2.5. That day averaged 136: 9.0 times the WHO daily guideline (15).

PM2.5 peak174 µg/m³
Days over the guideline3 days
PM10249 µg/m³
Optical depth2.44
161718192021
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 · 265Every 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 Gray fire last?
It burned between 18 August 2023 and 18 August 2023: 1 day, according to the start date recorded by United States agencies (MTBS / NIFC) and the heat detections seen by satellite.
How much area did it burn?
The official perimeter published by United States agencies (MTBS / NIFC) is 4,083 hectares (40.8 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?
The fire only entered Spokane (4,068 ha, 0.9 %).
What was the weather like?
During the fire the temperature reached 31.4 °C, humidity dropped to 10 % and gusts hit 61 km/h. The fire danger index (FWI) reached 73, class Very extreme.
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

Satellite cross-check

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.

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.