Planar Tides in Relation to the Dangers of the Plaguelands

Planar Tides in Relation to the Dangers of the Plaguelands is a treatise by the dwarven mathematical cosmologist Harbek Ferrystone about the influence of Limbo on the Material Plane in relation to the Plaguelands.

Though now obscure, Harbek’s treatise is an exceptionally detailed work of cosmological mathematics. He begins by noting that the dangers of the Plaguelands seemed to wax and wane over time, with bursts of extreme danger, such as the Blood Plague and the Cursed Cold, punctuated by periods of quiescence. Building on earlier work on planar connections from scholars such as Emyr of Tafolwern, he then proceeds to develop a mathematical theory of planar tides, which Harbek claimed could be used to predict the degree of danger of the Plaguelands. Specifically, Harbek sought to predict the strength of the connection between Limbo and the Material Plane that he believed influenced the Plaguelands.

His work focused on a description of planar movement that involved three cycles: planar drift, operating on decadal timescales; planar tides, operating on monthly timescales; and planar flows, operating on variable timescales and affecting the direction and strength of connections. He claimed that planar outbursts, leading to terrible dangers like the Cursed Cold, could only occur when planar drift and planar tides coincided to bring Limbo and the Material Plane into close alignment. At these times, though a planar outburst was not guaranteed, the conditions were right for a particularly strong planar flow to wash over into the Material Plane.

His mathematical treatment of this was complex, for neither planar drift nor planar tides occurred on strictly regular cycles. Nonetheless, he was able to accurately predict both the major spillovers and minor events, sometimes even within the month. He was even able to warn, in advance, of a period of vulnerability in DR 1709, during which, indeed, a series of unseasonable thunderstorms during which acidic oozes fell from the sky swept from the south. But with warning, the damage was far less than it could have been.

However, Harbek’s mathematical predictions were discredited in DR 1720, when the War of the Ashen Horde broke out in the March of Andonne and the Refounded Alliance of Aurbez at a time when, according to Harbek’s predictions, Limbo was distant from the Material Plane and no planar outbursts should have been possible.

Subsequently, Harbek’s work fell into obscurity. Nonetheless, Ferrystone’s work continues to be cited in discussions of Limbo’s influence on the Plaguelands.