Nation What’s a ‘zombie fire’? Dangerous underground fires spark record-setting wildfires in Arctic Circle September 8, 2020September 9, 2020Jordan Culver, USA TODAYComments Off on What’s a ‘zombie fire’? Dangerous underground fires spark record-setting wildfires in Arctic Circle "Zombie fires" are also known has "holdover fires." They can burn underground for years, melting permafrost in arctic regions.