Sighting in Lias, August 19, 2023

The witness had set up an automatic system on their home terrace that photographed the sky during the night of 19 to 20 August 2023. When they went through the recordings afterwards, they found two unidentified aerospace phenomena (UAP) that looked identical and followed the same winding, erratic path. No one therefore saw them directly. The images could nonetheless be analysed in detail, and their timestamps were precisely corrected using the files' metadata. GEIPAN rates the consistency of the case as high.

The investigation went through several hypotheses. Bats, nocturnal birds (two eagle owls, one a young bird learning from an adult) and insects close to the lens were ruled out: the calculated altitudes and speeds did not fit, the hour was too late for the birds, and insects would have flown far too slowly to cover the path in nearly 30 minutes. The hypothesis of two LED-lit balloons, by contrast, fits most of the data: a whitish colour, common for this type of balloon; overall drift to the south-east, in the direction of the wind; erratic movement caused by wind shear between 750 and 875 m altitude; speeds consistent with the winds Météo France estimated at those altitudes, with a Météo France expert confirming these points; and an observation made on a weekend, when such festive balloons are likely to be used. The real shape of the UAP could not be determined because the exposure time distorted the images.

GEIPAN classified the case as B: probable observation of two LED balloons carried by high-altitude wind. It points out that the lack of a direct visual witness would normally have led to the case being rejected; the study was carried out because of its curious nature and the value of the investigative method.