Talensac 1999, silent white spiral in the night sky

Summary

One winter night in 1999, around 1:00 a.m., a resident of Talensac (Ille-et-Vilaine) closing their gate was startled by a large silent white spiral moving across the sky. No other testimonies were collected. A rare meteorological phenomenon could be the cause, but the unknown exact date and the lack of detail prevent a proper assessment. GEIPAN classified the case as category C due to insufficient information.