Strong wind occurrence in Poland from the 13th to 16th centuries based on documentary evidence

Abstract. A comprehensive database of strong winds based on documentary evidence was created for Poland until AD 1600. Three types of documentary sources were used: handwritten and unpublished, published, and “secondary” literature. The database contains detailed information about the occurrence of strong winds (the location/region, time, duration and indexation for intensity, extent and character of damage), as well as the exact textual content of the original weather note, the name of the source, and an evaluation of the source’s quality. Five categories of strong winds were delimited: 1 − fresh and strong breeze (Beaufort scale 5–7), 2 − gale (8–9), 3 − storm (10–12), 4 − squall (i.e., gusty wind during a thunderstorm), and 5 – tornadoes. The intensity, extent, and character of damage were estimated based on the proposition given by Brázdil et al. (2004), which we slightly modified to include the Baltic Sea and its influence on coastal parts. In the database, 137 thus-defined strong winds were identified. A reliable estimate of some characteristics of the occurrence of strong winds in Poland seems possible from the mid-15th century onwards. The highest number of strong winds occurred in the second half of the 16th century, with a maximum in the 1570s. For each season, the greatest number of strong winds was found for the Baltic Coast and Pomerania region, and then for Silesia and Lesser Poland. Storms and gales were most common during the cold half-year (mainly in March, November, and December).