Fire near Alosno (ES)

What the satellites measured

This fire was tracked from 23 July at 03:54 to 24 July at 16:52, that is 2 days, through 52 satellite detections. The detected extent reaches 403 ha.

Detected extent

403 ha

Cumulative power

3,060 MW

Peak power

528 MW

Detections

52

“Detected extent” is not “burned area”: it is the union of the ground footprints of the satellite pixels, and a 375 m pixel counts in full 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 satellite detection and are not an official assessment: only the local fire and civil protection authorities are authoritative.

Replay how the fire spread

The map is centred on this fire and loads only its detections. The timeline below covers the whole fire, from the first satellite pass to the last. “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. “12 h” stacks twelve hours , as the home map does, where stacking avoids an empty screen between two satellite passes. Both are true, but they say different things.

The spread, pass after pass

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 30 days; beyond that, clustering would merge two successive fires in the same place.

Satellite passes in detail

One other fire near Alosno (ES)

Separate fires, apart in time or in space, not pieces of this one. A single municipality can have several over one summer, and the forest of Fontainebleau alone covers 172 square kilometres.

• 21 to 23 July1,493 ha

Follow live

The map shows active fires in 3D, with smoke plumes, forecast wind, drop zones and the live position of the Canadair, Dash 8 and Air Tractor aircraft of the French Sécurité civile.