Tephramancy

Tephramancy (or Tephromancy) refers to:

Divination by the ashes of the altar on which a victim had been consumed in sacrifice.
Divination from ashes of the bark of trees.

Etymology

Derived from the Greek tephrā ('ash') and manteia ('prophecy')

Methods

Tephramancy is performed by examining the ashes from an altar that have been blown or thrown up into the air after consumation of the victims of a sacrifice.

See Also:

You may be also interested in :

Earth Divination: Earth Magic: Practical Guide to Geomancy - John Michael Greer
Divination for Beginners: Reading the Past, Present & Future -Scott Cunningham