Skip to content
worldfires
en
US · United States · →

Lolo Peak Fire, July 2017 Missoula, Ravalli, Idaho

Out · last detection 13 Sept 2017, 21:26 UTC

The fire started on 15 July 2017 in Ravalli, United States, and satellites saw it burning for 61 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 25,227 hectares, spread across 3 counties.

It is the 9th largest in Montana since 2016 (of 302 with a page). Number 27 in United States in 2017, of 619.

Compare with…

Suggestions: Sharrott Creek · 2024Storm Creek · 2021Bm Hill · 2021Beaver · 2020

Burnt area
25,227ha
official perimeter (MTBS / NIFC)
Duration
≈ 61days
15 Jul 2017 – 13 Sept 2017
Counties hit
3
counties
Started on
15 Jul
2017
Heat detections
4,928
in a single hotspot: 532 MW
Danger at start
21
High · FWI index
Average daily power
1.3GW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 15 Jul13 Sept
13 Sept 2017

How it evolved, day by day

17 Jul 2017 · 1 MW · 1 18 Jul 2017 · 14 MW · 5 19 Jul 2017 · 15 MW · 3 20 Jul 2017 · 7 MW · 1 21 Jul 2017 · 1,232 MW · 18 22 Jul 2017 · 74 MW · 17 23 Jul 2017 · 217 MW · 13 24 Jul 2017 · 406 MW · 32 25 Jul 2017 · 1,085 MW · 44 26 Jul 2017 · 10,234 MW · 118 27 Jul 2017 · 67 MW · 7 28 Jul 2017 · 90 MW · 35 29 Jul 2017 · 82 MW · 22 30 Jul 2017 · 386 MW · 39 31 Jul 2017 · 265 MW · 37 1 Aug 2017 · 1,292 MW · 104 2 Aug 2017 · 292 MW · 62 3 Aug 2017 · 60 MW · 25 4 Aug 2017 · 55 MW · 16 5 Aug 2017 · 23 MW · 15 6 Aug 2017 · 21 MW · 9 7 Aug 2017 · 72 MW · 17 8 Aug 2017 · 230 MW · 33 9 Aug 2017 · 54 MW · 20 10 Aug 2017 · 114 MW · 12 11 Aug 2017 · 343 MW · 47 12 Aug 2017 · 337 MW · 48 14 Aug 2017 · 613 MW · 15 15 Aug 2017 · 333 MW · 66 16 Aug 2017 · 1,112 MW · 137 17 Aug 2017 · 6,712 MW · 323 18 Aug 2017 · 4,193 MW · 361 19 Aug 2017 · 6,728 MW · 272 20 Aug 2017 · 497 MW · 149 21 Aug 2017 · 368 MW · 59 22 Aug 2017 · 329 MW · 76 23 Aug 2017 · 298 MW · 95 24 Aug 2017 · 78 MW · 21 25 Aug 2017 · 70 MW · 12 26 Aug 2017 · 3,662 MW · 93 27 Aug 2017 · 412 MW · 144 28 Aug 2017 · 1,038 MW · 137 29 Aug 2017 · 1,094 MW · 74 30 Aug 2017 · 471 MW · 94 31 Aug 2017 · 1,730 MW · 93 1 Sept 2017 · 1,226 MW · 174 2 Sept 2017 · 8,015 MW · 250 3 Sept 2017 · 9,510 MW · 414 4 Sept 2017 · 863 MW · 240 5 Sept 2017 · 244 MW · 74 6 Sept 2017 · 369 MW · 97 7 Sept 2017 · 997 MW · 111 8 Sept 2017 · 190 MW · 76 9 Sept 2017 · 296 MW · 82 10 Sept 2017 · 1,316 MW · 105 11 Sept 2017 · 194 MW · 57 12 Sept 2017 · 2,266 MW · 127 13 Sept 2017 · 460 MW · 100
17 Jul 26 Jul 4 Aug 14 Aug 23 Aug 1 Sept 10 Sept

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

The weather it burned in

27°high
55km/h · peak gust
5%lowest humidity

It had gone 0 days without rain (1 mm or more) when it started. Rain came after the fire: 8.5 mm on 14 Sept.

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 16% of the area of London (252 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. Missoula
    16,840 ha reached on 17 Jul
    2.5 %
  2. Ravalli where it started
    7,786 ha reached on 24 Jul
    1.2 %
  3. Idaho
    530 ha reached on 26 Aug
    0.0 %

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 2015
Built-up area0.53 ha
Residents≈ 20

Inside the perimeter there were about 0.53 hectares of built-up land and about 20 residents (GHSL 2015, 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.

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)
15 Jul 26.7 °C 22 % 35 km/h 0.8 mm High 21
16 Jul 20.2 °C 13 % 54 km/h 0.2 mm High 33
17 Jul 21.1 °C 12 % 35 km/h 0.0 mm High 31
18 Jul 23.8 °C 11 % 44 km/h 0.0 mm High 35
19 Jul 25.1 °C 13 % 26 km/h 0.0 mm High 30
20 Jul 22.9 °C 17 % 55 km/h 0.0 mm Very high 39
21 Jul 21.6 °C 12 % 50 km/h 0.0 mm Very high 39
22 Jul 23.9 °C 18 % 29 km/h 0.0 mm High 32
23 Jul 26.7 °C 14 % 48 km/h 0.2 mm High 37
24 Jul 25.4 °C 6 % 55 km/h 0.0 mm Very high 46
25 Jul 25.4 °C 6 % 30 km/h 0.0 mm Very high 40
26 Jul 26.2 °C 9 % 36 km/h 0.0 mm Very high 41
27 Jul 23.1 °C 21 % 35 km/h 2.2 mm Low 11
28 Jul 25.2 °C 16 % 31 km/h 0.1 mm High 26
29 Jul 26.7 °C 13 % 37 km/h 0.0 mm High 35
30 Jul 26.8 °C 9 % 43 km/h 0.0 mm Very high 41
31 Jul 26.9 °C 6 % 32 km/h 0.0 mm Very high 41
1 Aug 26.0 °C 8 % 31 km/h 0.0 mm Very high 41
2 Aug 22.0 °C 23 % 40 km/h 0.0 mm High 38
3 Aug 25.2 °C 14 % 24 km/h 0.0 mm High 32
4 Aug 25.3 °C 18 % 46 km/h 0.1 mm High 37
5 Aug 20.3 °C 26 % 31 km/h 1.1 mm Moderate 19
6 Aug 21.8 °C 14 % 30 km/h 0.0 mm High 28
7 Aug 22.8 °C 12 % 26 km/h 0.0 mm High 32
8 Aug 22.7 °C 16 % 28 km/h 0.0 mm High 33
9 Aug 22.3 °C 16 % 24 km/h 0.0 mm High 34
10 Aug 23.2 °C 15 % 21 km/h 0.3 mm High 33
11 Aug 24.6 °C 12 % 21 km/h 0.0 mm High 36
12 Aug 24.3 °C 13 % 22 km/h 0.0 mm High 36
13 Aug 12.9 °C 43 % 44 km/h 3.3 mm Low 6
14 Aug 16.6 °C 33 % 38 km/h 0.1 mm Low 10
15 Aug 20.3 °C 13 % 33 km/h 0.0 mm High 24
16 Aug 20.9 °C 16 % 40 km/h 0.0 mm High 30
17 Aug 21.2 °C 18 % 39 km/h 0.0 mm High 31
18 Aug 23.3 °C 12 % 48 km/h 0.0 mm Very high 38
19 Aug 18.3 °C 18 % 53 km/h 0.0 mm Very high 39
20 Aug 18.2 °C 18 % 31 km/h 0.0 mm High 33
21 Aug 21.1 °C 17 % 19 km/h 0.0 mm High 31
22 Aug 25.4 °C 11 % 33 km/h 0.0 mm High 38
23 Aug 24.6 °C 15 % 39 km/h 0.3 mm Very high 38
24 Aug 20.0 °C 27 % 49 km/h 1.3 mm Moderate 20
25 Aug 20.8 °C 12 % 42 km/h 0.0 mm High 32
26 Aug 23.1 °C 9 % 30 km/h 0.0 mm High 36
27 Aug 26.0 °C 9 % 24 km/h 0.0 mm High 38
28 Aug 25.4 °C 10 % 37 km/h 0.0 mm Very high 40
29 Aug 26.6 °C 13 % 26 km/h 0.8 mm High 31
30 Aug 24.3 °C 13 % 50 km/h 0.0 mm High 38
31 Aug 21.7 °C 15 % 53 km/h 0.0 mm Very high 43
1 Sept 23.4 °C 16 % 39 km/h 0.0 mm Very high 38
2 Sept 27.0 °C 8 % 50 km/h 0.0 mm Very high 48
3 Sept 26.9 °C 5 % 49 km/h 0.0 mm Very high 50
4 Sept 19.1 °C 23 % 40 km/h 0.0 mm Very high 38
5 Sept 20.6 °C 19 % 23 km/h 0.0 mm High 33
6 Sept 22.9 °C 14 % 22 km/h 0.0 mm High 33
7 Sept 24.3 °C 16 % 23 km/h 0.2 mm High 34
8 Sept 21.9 °C 21 % 28 km/h 0.1 mm High 33
9 Sept 21.9 °C 27 % 46 km/h 0.9 mm High 26
10 Sept 18.1 °C 28 % 50 km/h 0.0 mm High 28
11 Sept 23.5 °C 10 % 27 km/h 0.0 mm High 34
12 Sept 22.6 °C 16 % 49 km/h 0.0 mm Very high 40
13 Sept 16.9 °C 23 % 53 km/h 0.0 mm Very high 38
14 Sept after 9.2 °C 41 % 33 km/h 8.5 mm Very low 1

Before and after, from space

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

Before · 8 Jul 2017
After · 20 Sept 2017

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 · 4,928Every 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 Lolo Peak Fire last?
The official perimeter only gives the start date (15 July 2017). The end comes from the heat detections inside the perimeter: it burned until 13 September 2017 (61 days from 15 July 2017), 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 25,227 hectares (252.3 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?
The fire entered 3 counties: Missoula (16,840 ha, 2.5 %); Ravalli (7,786 ha, 1.2 %); Idaho (530 ha, 0.0 %).
What was the weather like?
During the fire the temperature reached 27.0 °C, humidity dropped to 5 % and gusts hit 55 km/h. The fire danger index (FWI) reached 50, 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: MTBS (US Geological Survey and US Forest Service), 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. 4,928 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 2015, 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.