How long did the Phrao fire last?

According to the heat detections seen by satellite inside the perimeter, it burned from 17 March 2020 to 2 April 2020 (17 days). The perimeter dates it from 23 March 2020 to 27 March 2020.

How much area did it burn?

The perimeter GWIS (Copernicus) rebuilt from heat detections is 1,832 hectares (18.3 km²). It is an estimate: official national figures may differ.

Which municipalities burned?

The fire entered 2 municipalities: Phrao (1,349 ha, 1.0 %); Mae Taeng (492 ha, 0.4 %).

What was the weather like?

During the fire the temperature reached 38.6 °C, humidity dropped to 20 % and gusts hit 42 km/h. The fire danger index (FWI) reached 43, class Very high.

Where does this data come from?

From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Thailand (geoBoundaries). It is not an official report.

TH · Thailand · 2020-03-17 → 2020-04-02

Phrao fire, 17 March 2020 พร้าว · Phrao, Mae Taeng

Out · last detection 29 Mar 2020, 18:35 UTC

The fire started on 17 March 2020 in Phrao, Thailand, and satellites saw it burning for 17 days. Copernicus’s global GWIS system rebuilt a burnt perimeter of 1,832 hectares from heat detections, spread across 2 municipalities.

It is the 155th largest in Chiang Mai Province since 2016 (of 399 with a page). Number 171 in Thailand in 2020, of 457.

The power measured by the satellite is low (17.8 MW in the strongest hotspot), more typical of grass or stubble burning, or a slow surface fire, than of a large crown fire.

Compare with…

Suggestions: Wiang Pa Pao · 2020 Phrao · 2026 Doi Saket · 2026 Wiang Pa Pao · 2026

Burnt area: 1,832ha; GWIS perimeter (Copernicus)
Duration: 17days; 17 Mar 2020 – 2 Apr 2020
Municipalities hit: 2; districts
Started on: 17 Mar; 2020
Heat detections: 67; in a single hotspot: 18 MW
Danger at start: 41; Very high · FWI index
Average daily power: 30MW; detected power per day, on average

HOTSPOTS BY DAY 17 Mar2 Apr

Play back 29 Mar 2020

How it evolved, day by day

17 Mar 20 Mar 24 Mar 25 Mar 26 Mar 29 Mar

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

42km/h · peak gust

20%lowest humidity

It had gone more than two months without rain (1 mm or more) when it started.

This area had burned before

61% of the perimeter overlaps earlier fires recorded since 2016: 264 ha in 2016, 548 ha in 2017, 630 ha in 2019. Part of it burned more than once, so the yearly figures add up to more than the 1,117 ha that had burned before.

How big is it?

It burned the equivalent of 1.2% of the area of London (18 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 town

Phrao พร้าว where it started

1,349 ha reached on 20 Mar

1.0 %
Mae Taeng แม่แตง

492 ha reached on 17 Mar

0.4 %

Burnt area inside each municipality, from crossing the GWIS 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 area0.13 ha

Residents< 20

Inside the perimeter there were about 0.13 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)
11 Mar	37.5 °C	20 %	40 km/h	0.0 mm	Very high 41
12 Mar	38.3 °C	21 %	28 km/h	0.0 mm	High 38
13 Mar	38.6 °C	23 %	25 km/h	0.0 mm	Very high 38
14 Mar	37.4 °C	26 %	24 km/h	0.0 mm	Very high 38
15 Mar	37.9 °C	28 %	36 km/h	0.0 mm	Very high 41
16 Mar	36.5 °C	33 %	32 km/h	0.0 mm	High 36
17 Mar	37.6 °C	25 %	35 km/h	0.0 mm	High 37
18 Mar	38.6 °C	22 %	33 km/h	0.0 mm	Very high 38
19 Mar	37.7 °C	22 %	27 km/h	0.0 mm	High 38
20 Mar	36.9 °C	26 %	42 km/h	0.0 mm	Very high 42
21 Mar	36.8 °C	24 %	42 km/h	0.0 mm	Very high 43
22 Mar	35.0 °C	29 %	36 km/h	1.6 mm	High 23
23 Mar	36.0 °C	23 %	39 km/h	0.0 mm	High 37
24 Mar	36.2 °C	22 %	41 km/h	0.0 mm	Very high 38
25 Mar	36.4 °C	21 %	38 km/h	0.0 mm	Very high 40
26 Mar	37.5 °C	21 %	35 km/h	0.0 mm	Very high 39
27 Mar	37.8 °C	25 %	29 km/h	0.0 mm	Very high 38
28 Mar	38.0 °C	24 %	32 km/h	0.0 mm	Very high 39
29 Mar	38.8 °C	26 %	31 km/h	0.0 mm	Very high 40
30 Mar	39.2 °C	27 %	31 km/h	0.0 mm	Very high 39
31 Mar	39.9 °C	22 %	31 km/h	0.0 mm	Very high 40
1 Apr	40.2 °C	17 %	37 km/h	0.0 mm	Very high 46
2 Apr	39.4 °C	20 %	40 km/h	0.0 mm	Very high 46
3 Apr after	39.7 °C	18 %	34 km/h	0.0 mm	Very high 44
4 Apr after	39.5 °C	19 %	32 km/h	0.0 mm	Very high 44
5 Apr after	38.5 °C	22 %	32 km/h	0.0 mm	Very high 45
6 Apr after	37.9 °C	29 %	37 km/h	0.0 mm	Very high 42

Before and after, from space

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

↔

Before · 10 Mar 2020

After · 9 Apr 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 · 67Every 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 Thailand ›

Frequently asked questions

How long did the Phrao fire last?: According to the heat detections seen by satellite inside the perimeter, it burned from 17 March 2020 to 2 April 2020 (17 days). The perimeter dates it from 23 March 2020 to 27 March 2020.
How much area did it burn?: The perimeter GWIS (Copernicus) rebuilt from heat detections is 1,832 hectares (18.3 km²). It is an estimate: official national figures may differ.
Which municipalities burned?: The fire entered 2 municipalities: Phrao (1,349 ha, 1.0 %); Mae Taeng (492 ha, 0.4 %).
What was the weather like?: During the fire the temperature reached 38.6 °C, humidity dropped to 20 % and gusts hit 42 km/h. The fire danger index (FWI) reached 43, class Very high.
Where does this data come from?: From the GWIS (Copernicus) burnt perimeter, NASA FIRMS VIIRS hotspots and the administrative boundaries of Thailand (geoBoundaries). 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: 199 · 191 · Emergency number and official warnings ›

Satellite cross-check

NASA FIRMS ↗
GWIS · Copernicus ↗

History of this page · 2 Changes in area, dates, name, official record or merged pages, compared every night since 24 October 2026.

26 October 2026 Last day with fire: 27 March 2020 → 2 April 2020.
26 October 2026 Start date: 23 March 2020 → 17 March 2020.

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?

Dates or duration Place or towns Burned area Name It was not a wildfire Same fire as another page Something else

What really happened?

Your connection to the fire (optional) Email (optional)

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 199 · 191.

How we know this

Perimeter: GWIS (Copernicus), rebuilt from heat detections rather than mapped on imagery.
Dates adjusted with the VIIRS detections inside the perimeter, which said 23 March 2020 to 27 March 2020. 67 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 comes from the Copernicus Global Wildfire Information System (GWIS), which rebuilds it from MODIS and VIIRS heat detections and publishes it under CC BY 4.0. It is not measured on imagery as in Europe, so it is an estimate. Heat detections come from the VIIRS sensors aboard Suomi-NPP and NOAA-20, distributed by NASA FIRMS at 375 m resolution. Municipal boundaries come from geoBoundaries ADM2 (Creative Commons Attribution 3.0 Intergovernmental Organisations (CC BY 3.0 IGO)). The area per municipality is computed by WorldFires by crossing the perimeter with those boundaries, so it may differ from each country’s official figure.

Where it burned