How long did the Ridge fire last?

According to the heat detections seen by satellite inside the perimeter, it burned from 30 July 2023 to 5 August 2023 (7 days). The perimeter dates it from 30 July 2023 to 30 July 2023.

How much area did it burn?

The official perimeter published by United States agencies (MTBS / NIFC) is 1,508 hectares (15.1 km²). Other tallies, such as daily incident reports, may give slightly different figures.

Which counties burned?

The fire only entered Flathead (1,513 ha, 0.1 %).

What was the weather like?

During the fire the temperature reached 33.5 °C, humidity dropped to 13 % and gusts hit 55 km/h. The fire danger index (FWI) reached 46, class Very high.

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.

US · United States · 2023-07-30 → 2023-08-05

Ridge Fire, July 2023 Flathead

Out · last detection 5 Aug 2023, 09:10 UTC

The fire started on 30 July 2023 in Flathead, United States, and satellites saw it burning for 7 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 1,508 hectares, spread across a single county.

It is the 136th largest in Montana since 2016 (of 302 with a page). Number 109 in United States in 2023, of 305.

Compare with…

Suggestions: Doris Point · 2023 Paola Ridge · 2018 Sprague · 2017 Howe Ridge · 2018

Burnt area: 1,508ha; official perimeter (MTBS / NIFC)
Duration: 7days; 30 Jul 2023 – 5 Aug 2023
Municipalities hit: 1; counties
Started on: 30 Jul; 2023
Heat detections: 233; in a single hotspot: 124 MW
Danger at start: 46; Very high · FWI index
Average daily power: 347MW; detected power per day, on average

Play back 5 Aug 2023

HOTSPOTS BY DAY 30 Jul5 Aug

How it evolved, day by day

30 Jul 31 Jul 1 Aug 2 Aug 3 Aug 4 Aug 5 Aug

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

The weather it burned in

34°high

55km/h · peak gust

13%lowest humidity

It had gone 32 days without rain (1 mm or more) when it started. Rain came after the fire: 3.7 mm on 6 Aug.

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 1% of the area of London (15 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 town

Flathead where it started

1,513 ha reached on 30 Jul

0.1 %

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)
30 Jul	33.5 °C	13 %	55 km/h	0.1 mm	Very high 46
31 Jul	30.5 °C	18 %	29 km/h	0.0 mm	Very high 40
1 Aug	30.7 °C	13 %	30 km/h	0.0 mm	Very high 39
2 Aug	33.2 °C	14 %	27 km/h	0.1 mm	Very high 43
3 Aug	31.5 °C	16 %	26 km/h	0.0 mm	Very high 41
4 Aug	30.3 °C	21 %	23 km/h	0.0 mm	Very high 38
5 Aug	25.3 °C	38 %	36 km/h	0.3 mm	High 29
6 Aug after	24.1 °C	47 %	29 km/h	3.7 mm	Very low 4

Before and after, from space

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

↔

Before · 23 Jul 2023

After · 12 Aug 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 2 August 2023 the air beside the fire reached 68 µg/m³ of PM2.5. That day averaged 30: 2.0 times the WHO daily guideline (15).

PM2.5 peak68 µg/m³

Days over the guideline2 days

PM1097 µg/m³

Optical depth0.64

WHO 15

2829303112

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 · 233Every 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 United States ›

Frequently asked questions

How long did the Ridge fire last?: According to the heat detections seen by satellite inside the perimeter, it burned from 30 July 2023 to 5 August 2023 (7 days). The perimeter dates it from 30 July 2023 to 30 July 2023.
How much area did it burn?: The official perimeter published by United States agencies (MTBS / NIFC) is 1,508 hectares (15.1 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?: The fire only entered Flathead (1,513 ha, 0.1 %).
What was the weather like?: During the fire the temperature reached 33.5 °C, humidity dropped to 13 % and gusts hit 55 km/h. The fire danger index (FWI) reached 46, class Very high.
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

NASA FIRMS ↗
NIFC · Fire maps ↗

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?

Dates or duration Place or towns Burned area Name It was not a wildfire Same fire as another page Something else

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: MTBS (US Geological Survey and US Forest Service), official.
Dates adjusted with the VIIRS detections inside the perimeter, which said 30 July 2023 to 30 July 2023. 233 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.

How we build fire pages: methodology ›

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.

Where it burned