Smoke from wildfires in Siberia drifted to Alaska last year as well, according to the National Weather Service, but Alaska already had hazy skies from local wildfires.

A prolonged heatwave in Siberia is “undoubtedly alarming”, climate scientists have said. The freak temperatures have been linked to wildfires, a huge oil spill and a plague of tree-eating moths.

Wildfires in Russia have burned across a combined area the size of Greece so far in 2020, surpassing official estimates threefold. Experts warn that this year’s blazes could become the most destructive in history.