Why Hail Falls More Often This Season | RainViewer Blog

TL;DR: The Po Valley is one of the most hail-prone areas in Europe, and late summer is when the biggest stones fall. A hailstone grows by riding the updraft up and down, adding one layer of ice per pass Large stones need updrafts often above 150 km/h (93 mph), which only well-organised supercells produce Humid Mediterranean air, cooler air from the north and Alpine lifting combine to create them The largest hail falls in a narrow corridor: two towns a few kilometres apart can see opposite outcomes The size of a fallen stone is a direct measure of the updraft that held it up The Po Valley is on