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Holser Fire, August 2020 Ventura, Los Angeles

Out · last detection 18 Aug 2020, 20:19 UTC

The fire started on 17 August 2020 in Ventura, United States, and satellites saw it burning for 1 day. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 953 hectares, spread across 2 counties.

It is the 294th largest in California since 2016 (of 442 with a page). Number 282 in United States in 2020, of 441.

The power measured by the satellite is low (27.7 MW in the strongest hotspot), more typical of grass or stubble burning, or a slow surface fire, than of a large crown fire.

Burnt area
953ha
official perimeter (MTBS / NIFC)
Duration
1day
17 Aug 2020 – 17 Aug 2020
Municipalities hit
2
counties
Started on
17 Aug
2020
Heat detections
26
in a single hotspot: 28 MW
Danger at start
36
High · FWI index
Energy released
169MW
sum of detected power

Where it burned

HOTSPOTS BY DAY 17 Aug17 Aug

How it evolved, day by day

18

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

The weather it burned in

39°high
37km/h · peak gust
18%lowest humidity

It had gone 48 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.

What happened to each town

  1. Ventura where it started
    846 ha reached on 18 Aug
    0.2 %
  2. Los Angeles
    114 ha reached on 18 Aug
    0.0 %

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)
17 Aug 37.8 °C 26 % 37 km/h 0.0 mm High 36
18 Aug after 39.4 °C 18 % 28 km/h 0.9 mm Very high 42
19 Aug after 37.7 °C 22 % 37 km/h 0.0 mm Very high 40
20 Aug after 39.0 °C 17 % 31 km/h 0.0 mm Very high 41
21 Aug after 35.9 °C 24 % 48 km/h 0.0 mm Very high 48
22 Aug after 33.8 °C 31 % 34 km/h 0.0 mm Very high 40
23 Aug after 32.5 °C 33 % 34 km/h 0.0 mm High 36
24 Aug after 33.8 °C 26 % 35 km/h 0.0 mm High 37
25 Aug after 33.8 °C 25 % 38 km/h 0.0 mm High 38
26 Aug after 34.0 °C 21 % 37 km/h 0.0 mm Very high 39
27 Aug after 34.6 °C 17 % 49 km/h 0.0 mm Very high 47
28 Aug after 33.0 °C 12 % 36 km/h 0.0 mm Very high 47

Before and after, from space

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

Before · 10 Aug 2020
After · 24 Aug 2020

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 · 26Every 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 Holser fire last?
It burned between 17 August 2020 and 17 August 2020: 1 day, according to the start date recorded by United States agencies (MTBS / NIFC) and the heat detections seen by satellite.
How much area did it burn?
The official perimeter published by United States agencies (MTBS / NIFC) is 953 hectares (9.5 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?
The fire entered 2 counties: Ventura (846 ha, 0.2 %); Los Angeles (114 ha, 0.0 %).
What was the weather like?
During the fire the temperature reached 39.4 °C, humidity dropped to 18 % and gusts hit 37 km/h. The fire danger index (FWI) reached 42, 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

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.

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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.

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.