How long did the William fire last?

It burned between 6 September 2020 and 6 September 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 2,268 hectares (22.7 km²). Other tallies, such as daily incident reports, may give slightly different figures.

Which counties burned?

The fire entered 2 counties: Juab (1,602 ha, 0.2 %); Utah (667 ha, 0.1 %).

What was the weather like?

During the fire the temperature reached 32.7 °C, humidity dropped to 5 % and gusts hit 69 km/h. The fire danger index (FWI) reached 63, 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 · 2020-09-06 → 2020-09-06

William Fire, September 2020 Juab, Utah

Out · last detection 7 Sept 2020, 20:46 UTC

The fire started on 6 September 2020 in Juab, United States, and satellites saw it burning for 1 day. United States agencies (MTBS / NIFC) mapped an official burnt perimeter of 2,268 hectares, spread across 2 counties.

It is the 66th largest in Utah since 2016 (of 165 with a page). Number 168 in United States in 2020, of 441.

Burnt area: 2,268ha; official perimeter (MTBS / NIFC)
Duration: 1day; 6 Sept 2020 – 6 Sept 2020
Municipalities hit: 2; counties
Started on: 6 Sept; 2020
Heat detections: 122; in a single hotspot: 240 MW
Danger at start: 58; Extreme · FWI index
Energy released: 3.5GW; sum of detected power

Play back 7 Sept 2020

HOTSPOTS BY DAY 6 Sept6 Sept

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

33°high

69km/h · peak gust

5%lowest humidity

It had gone 44 days without rain (1 mm or more) when it started.

This area had burned before

1% of the perimeter overlaps earlier fires recorded since 2016: 31 ha in 2018.

31 ha Bald Mountain fire, August 2018 8,501 ha in total; the hectares shown are those it shares with this fire

What happened to each town

Juab where it started

1,602 ha reached on 7 Sept

0.2 %
Utah

667 ha reached on 6 Sept

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)
6 Sept	32.7 °C	7 %	51 km/h	0.0 mm	Extreme 58
7 Sept after	29.6 °C	8 %	66 km/h	0.0 mm	Extreme 63
8 Sept after	14.3 °C	34 %	69 km/h	7.6 mm	Very low 4
9 Sept after	14.1 °C	21 %	35 km/h	0.0 mm	Low 8
10 Sept after	16.6 °C	22 %	33 km/h	0.0 mm	Moderate 17
11 Sept after	23.4 °C	12 %	35 km/h	0.0 mm	High 30
12 Sept after	26.6 °C	6 %	30 km/h	0.0 mm	High 38
13 Sept after	28.7 °C	5 %	22 km/h	0.0 mm	Very high 42
14 Sept after	28.9 °C	6 %	27 km/h	0.0 mm	Very high 43
15 Sept after	28.4 °C	8 %	37 km/h	0.0 mm	Very high 44
16 Sept after	28.0 °C	8 %	33 km/h	0.0 mm	Very high 43
17 Sept after	28.5 °C	9 %	33 km/h	0.0 mm	Very high 44
18 Sept after	27.6 °C	10 %	37 km/h	0.0 mm	Very high 48
19 Sept after	20.3 °C	24 %	38 km/h	0.0 mm	High 37
20 Sept after	22.6 °C	18 %	29 km/h	0.0 mm	High 34
21 Sept after	27.2 °C	13 %	39 km/h	0.0 mm	Very high 39
22 Sept after	25.9 °C	16 %	38 km/h	0.1 mm	Very high 39
23 Sept after	26.0 °C	11 %	29 km/h	0.0 mm	High 37
24 Sept after	28.4 °C	9 %	46 km/h	0.0 mm	Very high 46
25 Sept after	27.4 °C	6 %	46 km/h	0.0 mm	Extreme 50
26 Sept after	23.2 °C	12 %	50 km/h	0.0 mm	Very high 49
27 Sept after	16.4 °C	22 %	46 km/h	0.0 mm	Very high 39
28 Sept after	18.5 °C	13 %	31 km/h	0.0 mm	High 34
29 Sept after	22.3 °C	9 %	26 km/h	0.0 mm	High 36
30 Sept after	24.1 °C	10 %	35 km/h	0.0 mm	Very high 38
1 Oct after	24.1 °C	8 %	30 km/h	0.0 mm	Very high 40
2 Oct after	22.0 °C	10 %	35 km/h	0.0 mm	Very high 41
3 Oct after	23.1 °C	13 %	32 km/h	0.0 mm	Very high 41
4 Oct after	23.9 °C	7 %	31 km/h	0.0 mm	Very high 41
5 Oct after	23.9 °C	7 %	31 km/h	0.0 mm	Very high 41
6 Oct after	23.4 °C	9 %	27 km/h	0.0 mm	Very high 40

Before and after, from space

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

↔

Before · 30 Aug 2020

After · 13 Sept 2020

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 · 122Every 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 William fire last?: It burned between 6 September 2020 and 6 September 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 2,268 hectares (22.7 km²). Other tallies, such as daily incident reports, may give slightly different figures.
Which counties burned?: The fire entered 2 counties: Juab (1,602 ha, 0.2 %); Utah (667 ha, 0.1 %).
What was the weather like?: During the fire the temperature reached 32.7 °C, humidity dropped to 5 % and gusts hit 69 km/h. The fire danger index (FWI) reached 63, 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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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