The combined contributuon of everyone's minds to the emotional weather.
But none of these powers is under direct conscious human control - and certainly none is under the control of any one human at any one time.
Rather, Chalakanesia's paranormal manifestations result from the interaction between the metapsychic faultline and that Averaged Collective Communal Mind (the Jabara Amaramara Soplid Melkus or JASM so beloved of alphadiabolists of Hell). On Chalakanesia, this interaction is often described as the emotional weather.
The emotional weather of Chalakanesia is far removed from the personal magic beloved of fantasy and romance. Therefore, when Atlanta was enraged, bar stools did not go whirling round her head, glasses did not burst asunder, the oyster shells did not get up off the sawdust to dance and sing, and the curtains did not catch fire (in fact, there were no curtains, window coverings in the Hari Mok being restricted to some bamboo blinds). [WoH Ch9]