The winter of 2019/2020 saw a very strong and cold polar vortex in the Arctic stratosphere. This was due to low wave activity from the lower atmosphere, which kept the vortex undisturbed. Despite some disturbances, the vortex remained strong, leading to record-breaking positive Arctic Oscillation in the upper atmosphere. The strong vortex also allowed for significant ozone loss, with the lowest levels ever observed in certain months. This extreme winter showed a strong connection between the lower and upper atmosphere.