Vaia, 29 ottobre 2018: perché un vento così forte?

"Vaia" storm led to to extensive distributed damage in northern Italy and southern Europe. After a short description of its genesis, we focus here on the derived strong wind that led to extensive destruction of mountain forests in north-east Italy. We stress its peculiar genesis, but also the fact that, notwithstanding the unusual conditions, the model forecasts had identified the event several days in advance. It is to be commended that, thank to this, the number of lost lives was limited.