Fire near Arsac

What the satellites measured

This fire was tracked from 23 September at 14:53 to 24 September at 14:32, through 11 satellite detections. The detected extent reaches 169 ha.

Detected extent

169 ha

Cumulative power

53 MW

Peak power, one pixel

5 MW

VIIRS and MODIS detections

11

These four figures cover the polar orbits alone, the ones that measure an area. The pass table below also counts geostationary detections, more frequent but too coarse for geometry, and its power column sums a whole pass where the peak above is that of a single pixel.

“Detected extent” is not “burned area”: it is the union of the ground footprints of the satellite pixels, and a pixel counts in full (375 m for VIIRS, 1 km for MODIS) even when only a forest edge is burning. Compared with press figures it is in practice one and a half to three times the area reported. Detections taken at the edge of the scan swath, too coarse to measure anything at all, are excluded. These figures come from thermal detection and are not an official assessment: only the emergency services and the competent authorities are authoritative.

Timeline

Closed, no update1 hastarted on 22 September at 17:06 · contained on 22 September at 17:23 · closed with no update, on 27 September at 15:30

1. Closed, no update27 September at 15:30

   No further news, a day of silence for an active fire, four for a contained one, and no recent satellite detection nearby: the register closed the entry on its own. This is a presumption, not an announcement, and a new report would reopen it.

2. Area revised to 1 ha22 September at 17:23

   Incendie au Pian-Médoc : feu fixé grâce à huit largages de Canadair et 40 pompiers au sol, 1 ha de forêt de pin brûlée · ici.fr

3. Reported contained22 September at 17:23

   Incendie au Pian-Médoc : feu fixé grâce à huit largages de Canadair et 40 pompiers au sol, 1 ha de forêt de pin brûlée · ici.fr

4. First report22 September at 17:06

   Gironde : un feu maîtrisé au Pian-Médoc avec deux Canadair engagés · Sud Ouest faits-divers

A "contained" fire is no longer spreading but is not out: crews remain on site and it can flare up again. Statuses and areas come from press reports and official sources, matched automatically; they are not an official record : only the prefecture and the fire service are authoritative. An entry with no news for ten days is closed automatically, and each entry's history keeps track of who announced what, and when.

Replay how the fire spread

The map is framed on this fire's footprint and loads only its detections. The timeline below covers the period in which satellites saw it, from the first to the last detection, with twelve hours before and twenty-four after; the ticks on the bar mark the emergency services' announcements that fall within it. The cursor opens on the most powerful pass, and playback replays the whole fire in about thirty seconds. “1 h” shows what is burning within an hour of the chosen moment : the map then follows the power curve below and empties when it falls. “24 h” stacks twenty-four hours : a fire stays visible between two satellite passes, which come two to four times a day. Both are true, but they say different things.

How the radiative power evolved

One point per satellite pass: the sum of the fire radiative power measured over the fire. This is the curve that says whether the fire eased off or picked up again, which no cumulative figure shows. The window covers 3 days; beyond that, clustering would merge two successive fires in the same place.

Satellite passes in detail

Follow live

The map shows active fires in 3D, with smoke plumes, forecast wind, drop zones and the live position of water bombers tracked by ADS-B, anywhere in the world.