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0231 Zen Fire, May 2026 Wasco

Out · last detection 18 Jul 2026, 10:49 UTC

The fire started on 25 May 2026 in Wasco, United States, and satellites saw it burning for 55 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 599 hectares, spread across a single county.

It is the 280th largest in Oregon since 2016 (of 327 with a page). Number 345 in United States in 2026, of 423.

The power measured by the satellite is low (1.7 MW in the strongest hotspot), more typical of grass or stubble burning, or a slow surface fire, than of a large crown fire.

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Burnt area
599ha
official perimeter (MTBS / NIFC)
Duration
≈ 55days
25 May 2026 – 18 Jul 2026
Counties hit
1
counties
Started on
25 May
2026
Heat detections
1
in a single hotspot: 2 MW
Danger at start
25
High · FWI index
Average daily power
2MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 25 May18 Jul

How it evolved, day by day

18 Jul 2026 · 2 MW · 1

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

The weather it burned in

36°high
66km/h · peak gust
7%lowest humidity

It had gone 7 days without rain (1 mm or more) when it started.

This area had burned before

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

How big is it?

10 km
It burned the equivalent of 0.4% of the area of London (6 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. Wasco where it started
    593 ha
    0.1 %

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)

Day High Min. humidity Peak gust Rain Danger (FWI)
25 May 29.7 °C 11 % 66 km/h 3.4 mm High 25
26 May 15.0 °C 41 % 34 km/h 2.7 mm Very low 4
27 May 24.2 °C 44 % 47 km/h 0.0 mm Moderate 12
28 May 27.1 °C 36 % 43 km/h 11.2 mm Very low 4
29 May 15.3 °C 59 % 47 km/h 3.7 mm Very low 1
30 May 17.4 °C 30 % 38 km/h 0.0 mm Very low 5
31 May 21.0 °C 19 % 27 km/h 0.0 mm Moderate 13
1 Jun 26.0 °C 15 % 27 km/h 0.0 mm High 21
2 Jun 29.8 °C 11 % 27 km/h 0.0 mm High 27
3 Jun 24.8 °C 21 % 49 km/h 0.0 mm High 31
4 Jun 24.4 °C 17 % 30 km/h 0.0 mm High 26
5 Jun 22.6 °C 25 % 41 km/h 0.0 mm High 28
6 Jun 17.9 °C 21 % 50 km/h 0.1 mm High 30
7 Jun 20.5 °C 16 % 27 km/h 0.0 mm High 25
8 Jun 18.6 °C 35 % 45 km/h 7.1 mm Very low 3
9 Jun 19.2 °C 33 % 52 km/h 0.7 mm Low 9
10 Jun 19.5 °C 30 % 38 km/h 0.0 mm Moderate 14
11 Jun 26.4 °C 14 % 29 km/h 0.0 mm High 24
12 Jun 28.1 °C 13 % 36 km/h 0.0 mm High 31
13 Jun 28.5 °C 14 % 44 km/h 0.0 mm High 34
14 Jun 30.1 °C 9 % 40 km/h 0.0 mm Very high 39
15 Jun 33.8 °C 9 % 26 km/h 0.0 mm High 36
16 Jun 31.9 °C 21 % 53 km/h 0.0 mm Very high 44
17 Jun 29.2 °C 11 % 37 km/h 0.0 mm Very high 40
18 Jun 29.5 °C 14 % 29 km/h 0.0 mm High 38
19 Jun 32.4 °C 16 % 38 km/h 0.0 mm Very high 42
20 Jun 28.2 °C 15 % 44 km/h 0.0 mm Very high 45
21 Jun 28.1 °C 13 % 32 km/h 0.0 mm Very high 40
22 Jun 31.6 °C 14 % 37 km/h 0.0 mm Very high 43
23 Jun 32.7 °C 12 % 41 km/h 0.0 mm Very high 46
24 Jun 32.4 °C 12 % 44 km/h 0.0 mm Extreme 53
25 Jun 27.9 °C 17 % 40 km/h 0.3 mm Very high 45
26 Jun 21.7 °C 38 % 48 km/h 2.8 mm Low 10
27 Jun 16.5 °C 43 % 57 km/h 1.3 mm Low 11
28 Jun 20.3 °C 37 % 50 km/h 0.2 mm Moderate 20
29 Jun 22.2 °C 38 % 39 km/h 0.7 mm Moderate 20
30 Jun 23.1 °C 28 % 45 km/h 0.0 mm High 28
1 Jul 22.4 °C 27 % 39 km/h 0.0 mm High 29
2 Jul 25.9 °C 24 % 34 km/h 0.0 mm High 30
3 Jul 30.7 °C 23 % 30 km/h 0.0 mm High 34
4 Jul 31.1 °C 16 % 36 km/h 0.0 mm Very high 42
5 Jul 31.5 °C 9 % 33 km/h 0.0 mm Very high 47
6 Jul 27.7 °C 14 % 32 km/h 0.2 mm Very high 42
7 Jul 35.2 °C 17 % 40 km/h 0.2 mm Extreme 54
8 Jul 30.8 °C 24 % 39 km/h 0.0 mm Very high 45
9 Jul 32.4 °C 7 % 30 km/h 0.0 mm Very high 49
10 Jul 33.2 °C 12 % 41 km/h 0.0 mm Extreme 54
11 Jul 31.5 °C 17 % 40 km/h 0.0 mm Extreme 51
12 Jul 29.4 °C 27 % 34 km/h 0.0 mm Very high 42
13 Jul 34.7 °C 15 % 41 km/h 0.0 mm Very high 48
14 Jul 35.9 °C 12 % 38 km/h 0.0 mm Extreme 53
15 Jul 35.0 °C 18 % 34 km/h 0.4 mm Extreme 50
16 Jul 32.7 °C 25 % 52 km/h 0.0 mm Extreme 55
17 Jul 31.6 °C 16 % 36 km/h 0.0 mm Very high 46
18 Jul 32.9 °C 13 % 36 km/h 0.0 mm Very high 49
19 Jul after 32.8 °C 16 % 34 km/h 0.0 mm Very high 47
20 Jul after 28.0 °C 23 % 26 km/h 0.2 mm High 38
21 Jul after 34.7 °C 19 % 30 km/h 0.4 mm Very high 44
22 Jul after 36.7 °C 20 % 32 km/h 0.2 mm Very high 45
23 Jul after 33.6 °C 31 % 38 km/h 0.0 mm Very high 43
24 Jul after 36.2 °C 17 % 39 km/h 0.2 mm Extreme 52
25 Jul after 32.4 °C 18 % 48 km/h 0.0 mm Extreme 53
26 Jul after 31.6 °C 17 % 40 km/h 0.0 mm Very high 50
27 Jul after 31.5 °C 19 % 35 km/h 0.0 mm Very high 45
28 Jul after 30.3 °C 25 % 38 km/h 0.0 mm Very high 43

Before and after, from space

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

Before · 18 May 2026
After · 25 Jul 2026

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 27 May 2026 the air beside the fire reached 12 µg/m³ of PM2.5, but no daily average passed the WHO guideline (15).

PM2.5 peak12 µg/m³
Days over the guideline0 days
PM1024 µg/m³
Optical depth0.48
232425262728
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 · 1Every 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 0231 Zen Fire last?
The official perimeter only gives the start date (25 May 2026). The end comes from the heat detections inside the perimeter: it burned until 18 July 2026 (55 days from 25 May 2026), 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 599 hectares (6.0 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?
The fire only entered Wasco (593 ha, 0.1 %).
What was the weather like?
During the fire the temperature reached 35.9 °C, humidity dropped to 7 % and gusts hit 66 km/h. The fire danger index (FWI) reached 55, class 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 · 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
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.
  • 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. One Suomi-NPP VIIRS detection 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.