On 9 February 2017, European Space Agency astronaut Thomas Pesquet, a member of the Expedition 50 crew, captured a winter landscape image from the International Space Station. It was of the Dnipro River. The photograph showed a great, coursing white snake that reminded Pesquet of a Japanese ‘Hokusai painting’. The white was ice and it explains why Russian forces on the Dnipro right bank now face a ‘difficult situation’, as described by General Sergei Surovikin, the recently appointed operational commander of Russian forces in Ukraine. In winter the Dnipro freezes over, usually after a 20-day spell of sub-zero temperatures. A...