Sighting in Mérindol, November 9, 2017

In the evening, at around 10:25 pm, a witness who was at home noticed an unusual luminous phenomenon in the night sky. They first described it as a "fiery cloud" and then as a "beam" of light. The observation lasted until about 11 pm, with the "fiery cloud" gradually fading out. The witness had time to take photographs. No other witness account was collected. The witness mentioned the reflection of a city's lights.

The investigation concluded that the witness had seen a light pillar, a rare optical phenomenon. It occurs when light is reflected by ice crystals suspended in the atmosphere. The light can come from the Sun or the Moon near the horizon, but also from artificial lighting such as street lamps, provided the ground source is far enough away not to be directly visible. That evening was cold: the Carpentras weather station recorded 1.7°. Flat ice crystals were located lower than usual because of the cold weather at altitude, and strong, localized light sources on the ground produced the effect. They may have come from the city of Salon-de-Provence, which lies to the south-west, the same direction as the phenomenon.

GEIPAN therefore classified the case as A: observation of an atmospheric light pillar.