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Hirz Fire, August 2018 Shasta

Out · last detection 16 Sept 2018, 10:01 UTC

The fire started on 9 August 2018 in Shasta, United States, and satellites saw it burning for 39 days. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 18,883 hectares, spread across a single county.

It is the 60th largest in California since 2016 (of 442 with a page). Number 40 in United States in 2018, of 511.

Compare with…

Suggestions: Salt · 2021Shoe · 2024Delta · 2018Green · 2025

Burnt area
18,883ha
official perimeter (MTBS / NIFC)
Duration
≈ 39days
9 Aug 2018 – 16 Sept 2018
Counties hit
1
counties
Started on
9 Aug
2018
Heat detections
3,070
in a single hotspot: 264 MW
Danger at start
48
Very high · FWI index
Average daily power
739MW
detected power per day, on average

Where it burned

HOTSPOTS BY DAY 9 Aug16 Sept
16 Sept 2018

How it evolved, day by day

9 Aug 2018 · 224 MW · 14 10 Aug 2018 · 188 MW · 30 11 Aug 2018 · 127 MW · 36 12 Aug 2018 · 731 MW · 118 13 Aug 2018 · 436 MW · 70 14 Aug 2018 · 797 MW · 62 15 Aug 2018 · 769 MW · 83 16 Aug 2018 · 746 MW · 102 17 Aug 2018 · 274 MW · 70 18 Aug 2018 · 255 MW · 65 19 Aug 2018 · 831 MW · 61 20 Aug 2018 · 811 MW · 112 21 Aug 2018 · 753 MW · 109 22 Aug 2018 · 530 MW · 75 23 Aug 2018 · 1,531 MW · 153 24 Aug 2018 · 1,324 MW · 159 25 Aug 2018 · 1,800 MW · 152 26 Aug 2018 · 1,358 MW · 156 27 Aug 2018 · 1,062 MW · 160 28 Aug 2018 · 1,069 MW · 168 29 Aug 2018 · 625 MW · 110 30 Aug 2018 · 771 MW · 110 31 Aug 2018 · 778 MW · 106 1 Sept 2018 · 4,122 MW · 216 2 Sept 2018 · 1,653 MW · 200 3 Sept 2018 · 312 MW · 86 4 Sept 2018 · 15 MW · 8 5 Sept 2018 · 16 MW · 11 6 Sept 2018 · 125 MW · 4 7 Sept 2018 · 237 MW · 7 8 Sept 2018 · 387 MW · 54 9 Sept 2018 · 122 MW · 27 10 Sept 2018 · 551 MW · 49 11 Sept 2018 · 3,416 MW · 82 12 Sept 2018 · 53 MW · 30 13 Sept 2018 · 2 MW · 2 14 Sept 2018 · 18 MW · 9 15 Sept 2018 · 16 MW · 3 16 Sept 2018 · 0 MW · 1
9 Aug 15 Aug 21 Aug 27 Aug 1 Sept 2 Sept 8 Sept 14 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

35°high
49km/h · peak gust
10%lowest humidity

It had gone 17 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 12% of the area of London (189 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. Shasta where it started
    18,968 ha reached on 9 Aug
    1.9 %

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 2020
Built-up area2.0 ha
Residents< 20

Inside the perimeter there were about 2.0 hectares of built-up land and almost nobody lived there (GHSL 2020, 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)
9 Aug 34.5 °C 12 % 36 km/h 0.0 mm Very high 48
10 Aug 34.7 °C 15 % 38 km/h 0.0 mm Very high 50
11 Aug 33.4 °C 11 % 37 km/h 0.0 mm Very high 49
12 Aug 32.3 °C 11 % 35 km/h 0.0 mm Very high 48
13 Aug 31.3 °C 12 % 36 km/h 0.0 mm Very high 48
14 Aug 31.4 °C 13 % 38 km/h 0.0 mm Very high 48
15 Aug 31.2 °C 18 % 38 km/h 0.0 mm Very high 46
16 Aug 31.2 °C 15 % 42 km/h 0.0 mm Very high 48
17 Aug 32.9 °C 11 % 31 km/h 0.0 mm Very high 45
18 Aug 33.3 °C 16 % 31 km/h 0.0 mm Very high 44
19 Aug 33.4 °C 13 % 34 km/h 0.0 mm Very high 47
20 Aug 32.1 °C 12 % 25 km/h 0.0 mm Very high 45
21 Aug 28.6 °C 18 % 37 km/h 0.0 mm Very high 43
22 Aug 28.9 °C 17 % 38 km/h 0.0 mm Very high 44
23 Aug 27.5 °C 20 % 40 km/h 0.0 mm Very high 43
24 Aug 27.0 °C 25 % 35 km/h 0.0 mm High 38
25 Aug 28.6 °C 22 % 33 km/h 0.0 mm High 38
26 Aug 28.0 °C 22 % 37 km/h 0.0 mm Very high 38
27 Aug 26.4 °C 25 % 33 km/h 0.0 mm High 36
28 Aug 28.6 °C 17 % 36 km/h 0.0 mm Very high 38
29 Aug 26.8 °C 29 % 40 km/h 0.0 mm High 36
30 Aug 25.1 °C 30 % 36 km/h 0.0 mm High 33
31 Aug 28.3 °C 21 % 27 km/h 0.0 mm High 32
1 Sept 31.9 °C 13 % 31 km/h 0.0 mm Very high 43
2 Sept 33.2 °C 10 % 32 km/h 0.0 mm Very high 47
3 Sept 33.1 °C 13 % 24 km/h 0.0 mm Very high 44
4 Sept 31.5 °C 15 % 35 km/h 0.0 mm Very high 46
5 Sept 29.9 °C 16 % 45 km/h 0.0 mm Very high 47
6 Sept 29.2 °C 18 % 34 km/h 0.0 mm Very high 43
7 Sept 31.2 °C 15 % 36 km/h 0.0 mm Very high 44
8 Sept 30.0 °C 12 % 28 km/h 0.0 mm Very high 41
9 Sept 30.5 °C 12 % 27 km/h 0.0 mm Very high 42
10 Sept 30.7 °C 12 % 34 km/h 0.0 mm Very high 43
11 Sept 26.0 °C 13 % 38 km/h 0.0 mm Very high 44
12 Sept 20.4 °C 25 % 33 km/h 0.1 mm High 36
13 Sept 20.7 °C 26 % 37 km/h 0.0 mm High 33
14 Sept 21.8 °C 19 % 37 km/h 0.0 mm High 33
15 Sept 21.4 °C 23 % 49 km/h 0.0 mm Very high 38
16 Sept 23.0 °C 22 % 34 km/h 0.0 mm High 34
17 Sept after 23.7 °C 12 % 35 km/h 0.0 mm High 37
18 Sept after 25.2 °C 17 % 27 km/h 0.0 mm High 36
19 Sept after 25.8 °C 10 % 36 km/h 0.0 mm Very high 41
20 Sept after 29.2 °C 7 % 43 km/h 0.0 mm Extreme 50
21 Sept after 27.4 °C 13 % 34 km/h 0.0 mm Very high 45
22 Sept after 26.4 °C 17 % 39 km/h 0.0 mm Very high 45
23 Sept after 26.2 °C 12 % 37 km/h 0.0 mm Very high 43
24 Sept after 28.5 °C 8 % 43 km/h 0.0 mm Very high 49
25 Sept after 31.3 °C 6 % 39 km/h 0.0 mm Extreme 51
26 Sept after 32.6 °C 6 % 27 km/h 0.0 mm Extreme 51

Before and after, from space

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

Before · 2 Aug 2018
After · 23 Sept 2018

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 · 3,070Every 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 Hirz Fire last?
The official perimeter only gives the start date (9 August 2018). The end comes from the heat detections inside the perimeter: it burned until 16 September 2018 (39 days from 9 August 2018), 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 18,883 hectares (188.8 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?
The fire only entered Shasta (18,968 ha, 1.9 %).
What was the weather like?
During the fire the temperature reached 34.7 °C, humidity dropped to 10 % and gusts hit 49 km/h. The fire danger index (FWI) reached 50, 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.

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.

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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. 3,070 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 2020, 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.