Temperature and Humidity in the Base-floors of Three Northern Finnish Churches Containing 17th–19th-century Burials

Natural mummification occurs in various favorable conditions. Cold environments have produced mummified human remains in northern Finland. These remains buried under the church floors mummified naturally probably through a process resembling freeze-drying. This chapter explores the conditions that led to the mummification of dozens and potentially hundreds of human remains. To conduct our study, we installed logging temperature and humidity measuring devices under the floors of three churches located by the shore of Bothnian Bay in northern Finland. Even our preliminary results show that the humidity and temperature conditions differ between these churches. It is also clear that relative humidity remains very high under the floors of each church. It appears that mummification has occurred in almost “cellar like” conditions. The preservation process was probably aided by the loose laid constructions allowing the air to freely move in the graves carrying the moisture from the remains.