Possible detection of the onset of flash flooding in Thessaly Greece by measurements of the Earth’s surface electric field

Abstract Since the beginning of 1980s a telemetric network comprising 18 stations in Greece started to measure remotely the transient electric field changes at the Earth’s surface. This article investigates the observed variations of Earth’s electric field on 5 September 2023 when the flash flood event occurred at Thessaly Greece as result of storm Daniel. The analyses show that, during the runoffs, the geoelectric field changes abruptly. Such observations could possibly be used as a criterion to estimate the flash flood onset. Upon employing detrended fluctuation analysis at various time scales, we identify three stages corresponding to light (or no) rain, heavy rain, and flood. The distinctive behaviour during the first two stages of the phenomenon under investigation may be used as an early warning. We also show that all stages are governed by fractality.