Kezma Station Logs Place 1908 Tunguska Event Amid Sudden Cloud Buildup and Thunderstorms

The preprint by Andrei Ol'khovatov examines daily logs and observer notes from the nearest operational station. The station recorded an abrupt increase in cloudiness on the morning of 30 June 1908, followed by deteriorating weather. Eyewitness accounts collected in Kezhma and along the Angara River describe two large fiery circles and unusual optical effects, which the author links to the same atmospheric disturbance captured in the logbook. The paper interprets these meteorological changes as consistent with a geophysical rather than purely asteroidal explanation.

Standard Tunguska literature focuses on seismic and tree-fall data while treating weather as incidental. Ol'khovatov’s work instead treats the meteorological record as primary evidence, noting that the event timing aligns with the onset of regional instability. This reframes the optical phenomena reported at Kezhma as potentially connected to atmospheric ionization or pressure waves rather than solely to a bolide entry.

Cross-referencing with earlier studies, such as the 1962 Kulik expedition summaries and the 2008 Vasilyev catalog of eyewitness reports, reveals that similar weather anomalies were noted but never systematically mapped against station data. The current analysis supplies that missing temporal anchor yet remains limited by a single station’s sparse observations and the absence of instrumental pressure or electric-field measurements.

Future progress requires digitization of additional Siberian station logs from 1908–1910 and integration with modern reanalysis datasets to test whether comparable meteorological signatures accompany other documented airbursts.