Features of Linear Convective Windstorms That Determine Their Impact on Northern Eurasian Forests

Severe linear convective windstorms (SLCWs) account for 66% of the total windthrow area in Northern Eurasian forests. However, in many cases, these events do not result in forest damage. The aim of this study is to reveal the features of storms that determine whether or not they cause forest damage. The study examines the relationship between windthrow occurrence and the characteristics of SLCW (seasonality, wind gusts and accompanying rainfall), as well as their formation environments. The sample includes 351 SLCW events that occurred in Northern Eurasian forests between 1986 and 2024. These are subdivided into two subsamples: 181 SLCW events with wind gusts of ≥25 m s−1, but without substantial damage to forests (SRND), and 170 SLCW events associated with windthrow (SRWD). Since the subsamples are similar in terms of forest stand characteristics, their differences are likely linked to differences in the characteristics of the SLCWs themselves. In general, SRWD events are accompanied by stronger wind gusts and rainfall than SRND events. The difference in rainfall amounts is more pronounced in the Integrated Multi-satellitE Retrievals for Global Precipitation Monitoring (GPM IMERG) satellite-derived data than in the data from weather stations. Springtime events contribute substantially more to SRND (26%) than to SRWD (12%). According to the ERA5 reanalysis, SRWD events form in conditions of greater thermodynamic instability and stronger wind shear than SRND events, i.e., under conditions that are generally more favorable for more severe windstorms. Obtained results can be further used to assess probable changes in forest damage caused by SLCW events based on projections of rainfall intensity and convective variables in a changing climate.