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Otr 241 Fire, July 2025 Ada

Out · last measured on 30 Jul 2025

The fire started on 29 July 2025 in Ada, United States, and satellites saw it burning for 2 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 787 hectares, spread across a single county.

It is the 264th largest in Idaho since 2016 (of 379 with a page). Number 245 in United States in 2025, of 325.

Compare with…

Suggestions: Sailor Cap · 2026Syrup · 2024Otr 134 · 2024Fraser · 2026

We have the official perimeter (MTBS / NIFC) for this fire, but not yet its hotspots: NASA publishes the yearly hotspot archive only once the year closes. The page picks them up automatically when they are available.

Burnt area
787ha
official perimeter (MTBS / NIFC)
Duration
2days
29 Jul 2025 – 30 Jul 2025
Counties hit
1
counties
Started on
29 Jul
2025
Danger at start
43
Very high · FWI index

Where it burned

The weather it burned in

37°high
42km/h · peak gust
13%lowest humidity

It had gone 24 days without rain (1 mm or more) when it started.

This area had burned before

21% of the perimeter overlaps earlier fires recorded since 2016: 164 ha in 2024.

How big is it?

10 km
It burned the equivalent of 0.5% of the area of London (7.9 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 county

  1. Ada where it started
    839 ha
    0.3 %

Burnt area inside each county, 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 Very dry air: 40 % of the area in United States

Day High Min. humidity Peak gust Rain Danger (FWI)
29 Jul 37.0 °C 13 % 42 km/h 0.2 mm Very high 43
30 Jul 36.3 °C 15 % 33 km/h 0.0 mm Very high 43
31 Jul after 34.5 °C 16 % 40 km/h 0.9 mm Extreme 57
1 Aug after 31.9 °C 23 % 28 km/h 0.0 mm High 30
2 Aug after 34.3 °C 13 % 40 km/h 0.0 mm Extreme 56
3 Aug after 35.0 °C 13 % 43 km/h 0.0 mm Very high 46
4 Aug after 29.2 °C 24 % 44 km/h 0.0 mm Extreme 69
5 Aug after 32.4 °C 17 % 29 km/h 0.0 mm Very high 39
6 Aug after 33.4 °C 16 % 39 km/h 0.0 mm Extreme 60
7 Aug after 30.1 °C 18 % 44 km/h 0.0 mm Extreme 55
8 Aug after 27.6 °C 15 % 38 km/h 0.0 mm Extreme 59
9 Aug after 30.4 °C 15 % 37 km/h 0.0 mm Extreme 55

Its twins: fires that started in the same weather

It started with an FWI of 42.9, a minimum humidity of 13% and 24 days without rain. Fires in the area that started in weather like this since 2016: 42.

FWI at the start 42.9
Minimum humidity 13 %
Days without rain 24
this fire chosen twins rest of the area
Almost identicalSimilar

Outlines of the closest twins

Sailor Cap Fire, May 2026
3,356 ha 1 day FWI 45.6 Min. humidity 14 % 71 km away, in 2026

First rain (1 mm or more) after it ended: none in the following ten days.

See its page Compare with this fire

What happened to them

2 days
median duration
1,380 ha
median area
69 %
went past 1,000 ha
2.0 mm
rain at the end (median; 24 of 42 had it)

It stayed below its twins: 787 ha against a median of 1,380 ha. It lasted 2 days, against 2 days.

In 18 of 42, not even 1 mm fell in the ten days after the end: they went out without rain. In the rest, the first rainy day brought a median of 2.0 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

—first rain
—no rain in ten days
42km/h · max. gust

It was considered over on 30 Jul, and not even 1 mm fell in the following ten days: it went out without rain. Twins with rain when they ended: 24 of 42, with a median of 2.0 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 · 22 Jul 2025
After · 6 Aug 2025

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 1 August 2025 the air beside the fire reached 17 µg/m³ of PM2.5, but no daily average passed the WHO guideline (15).

PM2.5 peak17 µg/m³
Days over the guideline0 days
PM1018 µg/m³
Optical depth0.32
27 Jul29 Jul31 Jul2 Aug
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)

Other fires nearby

All fires in United States

Frequently asked questions

How long did the Otr 241 Fire last?
It burned between 29 July 2025 and 30 July 2025: 2 days, 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 787 hectares (7.9 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?
The fire only entered Ada (839 ha, 0.3 %).
What was the weather like?
During the fire the temperature reached 37.0 °C, humidity dropped to 13 % and gusts hit 42 km/h. The fire danger index (FWI) reached 43, 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.
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: 42. Their median duration was 2 days and their median area 1,380 ha; 69 % went past 1,000 ha. In 18 of 42, not even 1 mm fell in the ten days after the end: they went out without rain. In the rest, the first rainy day brought a median of 2.0 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. Area: 857 → 787 ha.

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: NIFC WFIGS (United States), official; 2 polygons grouped in this page.
  • Dates from the perimeter: the VIIRS detections inside it did not change them. No 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 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.