Extreme precipitation event in Slovakia in September 2024.

In September 2024, much of Central Europe experienced above-average precipitation. In mid-September, Storm Boris brought heavy rainfall, flooding, and significant damage to Central and Eastern Europe. This study analyzes the intensity, spatial distribution, and meteorological drivers of the event using observational data from more than 600 precipitation stations across Slovakia. The event is placed in a historical context by comparing its maximum, multi-day, and cumulative precipitation totals recorded between September 11 and September 16, 2024, with previous extreme precipitation occurrences. Additionally, return period estimates and standard deviations [σ] were employed to assess the rarity of the event. The results indicate that the highest-ever recorded 2-day (267.3 mm in Borinka) and 5-day (379.8 mm in Pernek) precipitation totals in Slovakia occurred during this event. More than 20% of stations with available data recorded new maximum 2-day or 5-day precipitation totals, with multi-day totals surpassing the 100-year and 200-year quantiles. The extremity of the precipitation was most pronounced in 5-day totals, with some stations reporting values at or above the 6-sigma level.