Reducing the impact of severe weather on mass gathering events: the Lombardia, Italy, experience.

Severe weather events increasingly threaten the safety of mass gathering events (MGE), particularly open-air exhibitions and artistic performances. In 2015, Milano, Italy, hosted the World Expo from May to October. The exhibition was located 15 km away from Milano, covered 1.1 km2, and shaped as a long boulevard of 3 km length. Pools and waterways in and around the Expo area were elements of primary importance. During the 184 opening days, the attendance reached 21 mln visitors, with a daily average of 115,000 visitors. In 2017, the artists Christo and Jeanne-Claude created the temporary, site-specific artwork known as The Floating Piers, built in 2016 at Lake Iseo, 75 km from Milano, Italy. It was made up of 70,000 square meters of yellow fabric supported by a modular floating dock system. These walkable piers connected Monteisola Isle to the lake coast. The floating piers exhibitions attracted 1.2 mln visitors over its 16-day run, with peaks of more than 100,000 visitors per day.This work describes how the regional weather service planned and operated a dedicated monitoring and forecast weather service to reduce the impacts of severe weather during these two MGEs, increasing safety conditions for the visitors. Finally, Arpa Lombardia will be engaged in the weather forecast assistance for the next Winter Olympic Games in 2026, hosted in  Milano, Bormio, and Livigno.