Case study of a derecho wind storm on August 11-12, 2017 in Poland: part one

Windstorms belong to the most costly natural threats in Poland. On August 11-12, 2017, a strong thunderstorm happened which resulted in a catastrophic damage in three provinces: Wielkopolskie, Kujawsko-Pomorskie, and Pomorskie. This disaster has resulted in the death of 6 people, injuries to several dozen people, and enormous property losses including approximately 16,000 residential, utility and public buildings, 80,000 hectares of forest area, 67,000 hectares of agricultural crops, in excess of 300 overhead power line poles, and over 200 cables were downed. The trees felled by the wind blocked and partially damaged local and municipal roads over a length of about 1100 km. Over 500,000 consumers were deprived of electricity at the peak of the disaster. The purpose of this paper is to describe, analyse, and learn from such a dangerous extreme weather event. In order to achieve this, a cause of the thunderstorm, its important meteorological data, the severity of damage to buildings, civil infrastructure and environment, processes of damage surveys, ideas for reconstruction and removing of all damage, financial assistance from the central government, local authorities, and public collections were studied for better preparation of all services and people for mitigation of the effects of a natural disaster which may happen in the future. An example of a building with improved stiffness as the solution for better resistance of wind forces is presented.