How long did the Obi fire last?

It burned between 21 July 2018 and 21 July 2018: 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 4,566 hectares (45.7 km²). Other tallies, such as daily incident reports, may give slightly different figures.

Which counties burned?

The fire only entered Coconino (4,606 ha, 0.1 %).

What was the weather like?

During the fire the temperature reached 32.3 °C, humidity dropped to 4 % and gusts hit 59 km/h. The fire danger index (FWI) reached 53, 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.

US · United States · 2018-07-21 → 2018-07-21

Obi Fire, July 2018 Coconino

Out · last measured on 21 Jul 2018

The fire started on 21 July 2018 in Coconino, United States, and satellites saw it burning for 1 day. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 4,566 hectares, spread across a single county.

It is the 72th largest in Arizona since 2016 (of 380 with a page). Number 115 in United States in 2018, of 511.

Burnt area: 4,566ha; official perimeter (MTBS / NIFC)
Duration: 1day; 21 Jul 2018 – 21 Jul 2018
Municipalities hit: 1; counties
Started on: 21 Jul; 2018
Heat detections: 634; in a single hotspot: 188 MW
Danger at start: 10; Low · FWI index

HOTSPOTS BY DAY 21 Jul21 Jul

The weather it burned in

32°high

59km/h · peak gust

4%lowest humidity

It had gone one day without rain (1 mm or more) when it started. Rain came after the fire: 1.6 mm on 21 Aug.

This area had burned before

0% of the perimeter overlaps earlier fires recorded since 2016: 3 ha in 2016.

3 ha Fuller fire, June 2016 6,178 ha in total; the hectares shown are those it shares with this fire

What happened to each town

Coconino where it started

4,606 ha reached on 23 Jul

0.1 %

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 Jul	25.8 °C	22 %	35 km/h	1.3 mm	Low 10
22 Jul after	27.5 °C	23 %	38 km/h	0.1 mm	Moderate 17
23 Jul after	31.0 °C	14 %	42 km/h	0.0 mm	High 26
24 Jul after	30.2 °C	15 %	41 km/h	0.0 mm	High 26
25 Jul after	30.1 °C	13 %	49 km/h	0.0 mm	High 30
26 Jul after	31.1 °C	12 %	31 km/h	0.4 mm	High 31
27 Jul after	30.3 °C	12 %	43 km/h	0.0 mm	High 32
28 Jul after	29.2 °C	16 %	54 km/h	0.9 mm	High 26
29 Jul after	28.1 °C	19 %	36 km/h	1.9 mm	Moderate 14
30 Jul after	30.4 °C	9 %	24 km/h	0.0 mm	High 31
31 Jul after	30.6 °C	12 %	41 km/h	0.8 mm	High 30
1 Aug after	29.2 °C	14 %	46 km/h	0.5 mm	High 35
2 Aug after	27.7 °C	12 %	55 km/h	0.0 mm	High 37
3 Aug after	27.5 °C	19 %	43 km/h	0.4 mm	High 38
4 Aug after	29.5 °C	16 %	48 km/h	0.0 mm	Very high 40
5 Aug after	30.3 °C	8 %	59 km/h	0.0 mm	Very high 46
6 Aug after	31.5 °C	4 %	39 km/h	0.0 mm	Very high 45
7 Aug after	32.3 °C	6 %	37 km/h	0.0 mm	Very high 41
8 Aug after	30.4 °C	9 %	35 km/h	0.3 mm	Very high 44
9 Aug after	29.7 °C	9 %	43 km/h	0.5 mm	Very high 45
10 Aug after	31.2 °C	8 %	39 km/h	0.0 mm	Extreme 53
11 Aug after	27.2 °C	19 %	31 km/h	2.4 mm	Moderate 16
12 Aug after	28.2 °C	13 %	44 km/h	1.4 mm	High 24
13 Aug after	27.0 °C	15 %	38 km/h	0.9 mm	High 28
14 Aug after	27.6 °C	15 %	45 km/h	0.5 mm	High 36
15 Aug after	25.8 °C	18 %	35 km/h	2.5 mm	Low 11
16 Aug after	25.4 °C	26 %	32 km/h	1.2 mm	Moderate 15
17 Aug after	24.5 °C	25 %	33 km/h	3.0 mm	Low 7
18 Aug after	26.5 °C	23 %	40 km/h	0.0 mm	High 22
19 Aug after	28.9 °C	12 %	24 km/h	0.0 mm	High 30
20 Aug after	28.2 °C	15 %	67 km/h	0.4 mm	Very high 40
21 Aug after	24.8 °C	25 %	63 km/h	1.6 mm	Moderate 17

Before and after, from space

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

↔

Before · 14 Jul 2018

After · 28 Jul 2018

Before After

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 · 634Every 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 time	Satellite	FRP (MW)	Lat	Lon

Other fires nearby

All fires in United States ›

Frequently asked questions

How long did the Obi fire last?: It burned between 21 July 2018 and 21 July 2018: 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 4,566 hectares (45.7 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?: The fire only entered Coconino (4,606 ha, 0.1 %).
What was the weather like?: During the fire the temperature reached 32.3 °C, humidity dropped to 4 % and gusts hit 59 km/h. The fire danger index (FWI) reached 53, 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

Satellite cross-check

NASA FIRMS ↗
NIFC · Fire maps ↗

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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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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.

Where it burned