Warmer climates, stronger winds and widespread drought are some of the causes of the severe fires. Play the clip above and see how mega fires occur and how they can develop their own weather systems that, through lightning, spread the fire to new areas.
Find out more about how and why forest fires have become mega fires in the world of science - The mega fires: the global threat. The program airs on SVT2 on Monday, February 3 at 8pm and is available to watch on SVT Play.