Biamhacs rise up in cursed ruins, shearing souls away from the bodies of their owners. They appear suddenly and without warning, leaving victims little hope of escape. Strong-souled people are not harmed by biamhacs, but affected individuals are instantly reduced to a catatonic state and eventually their bodies shutdown. Souls that are ripped free from their bodies and caught in the center of the storm, may become stuck together and bonded with any other elemental substances in the maelstrom, often creating blights. Survival, while rare, is possible, if a person has a soul sufficiently "strong" to hang on to its associated body despite the storm's attempts to tear it loose.
The discovery of numerous biamhacs in Eír Glanfath during its early exploration resulted in thousands of Aedyr deaths. The deadliness and unpredictability of these events make biamhacs the most feared phenomenon of Eír Glanfath.