Sighting in Montbrison, April 10, 2022

A witness was in their garden in the late afternoon when they noticed an object in the sky moving slowly, which caught their attention. It rotated erratically and reflected sunlight from time to time, while following a straight path running from southeast to northwest. The witness described it as metallic, close to aluminium in colour, and parallelepiped in shape. The observation lasted more than five minutes, during which they took photos with their mobile phone. They then lost sight of the object. This was the only testimony collected.

GEIPAN examined the photos and the description and concluded that the witness very probably saw a mylar balloon. Mylar, a polyester film, reflects about 95% of light and gives a metallic appearance, which matches the colour and the reflections described. The slow, steady, straight movement, with the object turning on itself, is consistent with a balloon carried by the wind. The object travelled broadly in the direction of the prevailing wind (114°). That wind was very weak, around 5 km/h, and could vary locally, which creates slight turbulence and can make a balloon rotate. Mylar balloons come in very diverse shapes, including parallelepipeds. The case is classified A.