Hill Fire, August 2020 Valley
The fire started on 21 August 2020 in Valley, United States, and satellites saw it burning for 2 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 1,286 hectares, spread across a single county.
It is the 155th largest in Montana since 2016 (of 302 with a page). Number 234 in United States in 2020, of 441.
Compare with…
Suggestions: Cold Smoke · 2017
- Burnt area
- 1,286ha
- official perimeter (MTBS / NIFC)
- Duration
- 2days
- 21 Aug 2020 – 22 Aug 2020
- Municipalities hit
- 1
- counties
- Started on
- 21 Aug
- 2020
- Heat detections
- 36
- in a single hotspot: 78 MW
- Danger at start
- 55
- Extreme · FWI index
- Average daily power
- 328MW
- detected power per day, on average
Where it burned
How it evolved, day by day
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 17 days without rain (1 mm or more) when it started. Rain came after the fire: 1.9 mm on 27 Aug.
This area had burned before
No earlier perimeters overlap this fire since 2016, when the satellite record begins.
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 town
-
Valley where it started1,270 ha reached on 21 Aug0.1 %
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) |
|---|---|---|---|---|---|
| 21 Aug | 32.2 °C | 13 % | 39 km/h | 0.0 mm | Extreme 55 |
| 22 Aug | 35.5 °C | 12 % | 42 km/h | 0.0 mm | Extreme 65 |
| 23 Aug after | 30.9 °C | 9 % | 36 km/h | 0.0 mm | Extreme 62 |
| 24 Aug after | 36.9 °C | 8 % | 48 km/h | 0.0 mm | Very extreme 73 |
| 25 Aug after | 33.3 °C | 8 % | 35 km/h | 0.0 mm | Extreme 68 |
| 26 Aug after | 32.2 °C | 10 % | 42 km/h | 0.0 mm | Very extreme 77 |
| 27 Aug after | 29.3 °C | 25 % | 46 km/h | 1.9 mm | Very high 42 |
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.
Detections table · 36Every satellite heat detection, one by one, with time, satellite, power and coordinates.
| Date and time | Satellite | FRP (MW) | Lat | Lon |
|---|
Other fires nearby
Frequently asked questions
- How long did the Hill fire last?
- According to the heat detections seen by satellite inside the perimeter, it burned from 21 August 2020 to 22 August 2020 (2 days). The perimeter dates it from 21 August 2020 to 21 August 2020.
- How much area did it burn?
- The official perimeter published by United States agencies (MTBS / NIFC) is 1,286 hectares (12.9 km²). Other tallies, such as daily incident reports, may give slightly different figures.
- Which counties burned?
- The fire only entered Valley (1,270 ha, 0.1 %).
- What was the weather like?
- During the fire the temperature reached 35.5 °C, humidity dropped to 12 % and gusts hit 42 km/h. The fire danger index (FWI) reached 65, 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
- NIFC · National Interagency Fire Center ↗
- InciWeb · Incident Information System ↗
- MTBS · Monitoring Trends in Burn Severity ↗
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.
Report an error
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 21 August 2020 to 21 August 2020. 36 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.
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.