Juniper Canyon Fire, August 2025 Umatilla, Walla Walla
The fire started on 29 August 2025 in Umatilla, United States, and satellites saw it burning for 1 day. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 3,550 hectares, spread across 2 counties.
It is the 134th largest in Oregon since 2016 (of 327 with a page). Number 101 in United States in 2025, of 327.
The power measured by the satellite is low (17.5 MW in the strongest hotspot), more typical of grass or stubble burning, or a slow surface fire, than of a large crown fire.
Compare with…
- Burnt area
- 3,550ha
- official perimeter (MTBS / NIFC)
- Duration
- ≈ 1day
- 29 Aug 2025 – 29 Aug 2025
- Counties hit
- 2
- counties
- Started on
- 29 Aug
- 2025
- Heat detections
- 49
- in a single hotspot: 18 MW
- Danger at start
- 36
- High · FWI index
- Average daily power
- 254MW
- detected power per day, on average
Where it burned
How it evolved, day by day
29 Aug 2025 · 254 MW · 49
Fire radiative power detected each day, in megawatts, and number of hotspots. The magenta bar marks the peak day.
The weather it burned in
It had gone 12 days without rain (1 mm or more) when it started.
This area had burned before
96% of the perimeter overlaps earlier fires recorded since 2016: 2,471 ha in 2018, 3,366 ha in 2023. Part of it burned more than once, so the yearly figures add up to more than the 3,410 ha that had burned before.
How big is it?
London boundary: geoBoundaries · Office for National Statistics (Open Government Licence v3.0).
Paris boundary: geoBoundaries · Institut national de l'information géographique et forestière (IGN-F) (Etalab Open License 2.0).
Madrid boundary: geoBoundaries · Open Data ESRI, IGN Central Registry of Cartography Area (CC BY 4.0).
Berlin boundary: geoBoundaries · Federal Agency for Cartography and Geodesy (dl-de/by-2-0).
This compares size, not location: both shapes are at the same scale, north up, centred on each other.
What happened to each county
-
Umatilla where it started3,576 ha reached on 29 Aug0.4 %
-
3 ha0.0 %
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 2025Inside 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) |
|---|---|---|---|---|---|
| 29 Aug | 36.1 °C | 23 % | 20 km/h | 0.0 mm | High 36 |
| 30 Aug after | 35.1 °C | 19 % | 21 km/h | 0.0 mm | Very high 39 |
| 31 Aug after | 36.1 °C | 18 % | 22 km/h | 0.0 mm | Very high 40 |
| 1 Sept after | 36.2 °C | 18 % | 27 km/h | 0.0 mm | Very high 40 |
| 2 Sept after | 38.1 °C | 18 % | 21 km/h | 0.0 mm | Very high 41 |
| 3 Sept after | 37.5 °C | 18 % | 19 km/h | 0.0 mm | Very high 42 |
| 4 Sept after | 37.2 °C | 20 % | 30 km/h | 0.0 mm | Very high 44 |
| 5 Sept after | 34.6 °C | 27 % | 23 km/h | 0.0 mm | Very high 38 |
| 6 Sept after | 30.6 °C | 32 % | 20 km/h | 0.0 mm | High 38 |
| 7 Sept after | 32.2 °C | 26 % | 35 km/h | 0.0 mm | Very high 42 |
| 8 Sept after | 31.7 °C | 26 % | 27 km/h | 0.5 mm | Very high 38 |
Before and after, from space
Drag the line to compare the same ground before the fire and after it.
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 · CopernicusOn 27 August 2025 the air beside the fire reached 30 µg/m³ of PM2.5. That day averaged 24: 1.6 times the WHO daily guideline (15).
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 · 49Every satellite heat detection, one by one, with time, satellite, power and coordinates.
| Date and time | Satellite | FRP (MW) | Lat | Lon |
|---|
Other fires nearby
- 6,984 haHat Rock UmatillaJune 2023 · 2 days · 1 km away
- 4,844 haLake Wallula UmatillaJuly 2018 · 7 days · 1 km away
- 3,285 haTwin Sisters Walla WallaJune 2026 · 1 day · 7 km away
- 3,853 haHatch Grade Walla WallaSeptember 2026 · 2 days · 18 km away
- 1,071 haOasis Walla WallaJune 2023 · 1 day · 22 km away
- 5,126 haLambdin Walla WallaJune 2026 · 1 day · 23 km away
Frequently asked questions
- How long did the Juniper Canyon Fire last?
- The official perimeter only gives the start date (29 August 2025). The end comes from the heat detections inside the perimeter: it burned until 29 August 2025 (1 day from 29 August 2025), the last day with detections before more than 10 days in a row without any, so it is approximate.
- How much area did it burn?
- The official perimeter published by United States agencies (MTBS / NIFC) is 3,550 hectares (35.5 km²). Other tallies, such as daily incident reports, may give slightly different figures.
- Which counties burned?
- The fire entered 2 counties: Umatilla (3,576 ha, 0.4 %); Walla Walla (3 ha, 0.0 %).
- What was the weather like?
- During the fire the temperature reached 36.1 °C, humidity dropped to 23 % and gusts hit 20 km/h. The fire danger index (FWI) reached 36, class 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 · Emergency number and official warnings ›
- NIFC · National Interagency Fire Center ↗
- InciWeb · Incident Information System ↗
- MTBS · Monitoring Trends in Burn Severity ↗
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.
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
How we know this
- Perimeter: NIFC WFIGS (United States), official.
- The official perimeter has no end date: the end is the last day with VIIRS detections inside the perimeter before a gap of more than 10 days (150 days at most), so it is approximate. 49 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.
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.