The Mother Storm was the massive thunderstorm which first seeded the Edgeworld with life. Ever since the dawn of time, the Mother Storm returned to the Edge every five or six thousand years to release her energy at Riverrise and rejuvenate the Edgewater River. During the events of Midnight Over Sanctaphrax, the Mother Storm's path was blocked by Sanctaphrax, and the Anchor Chain had to be severed to allow her to proceed to her destination. The Mother Storm generated all other weather, including Great Storms. Whenever she prepared to return, the Mother Storm conjured up much more severe and unusual weather, such as Mind Storms, which played havoc with people's emotions.
Inside the Mother Storm, there are various different mind storms, including storms which created sadness, joy and anger. These mind storms were far more extreme than the ones sent to the Edge.
At the center of the Mother Storm was a region of ultimate calm where a sky ship could stay becalmed for months. The only sky ships ever to reach this region were the Stormchaser and the Edgedancer. If one remained there too long, one would gain total knowledge of the weather while gradually being absorbed into the Mother Storm herself. Quint was absorbed into the Mother Storm, and did not reemerge for five and a half centuries, at which point he was reunited with Twig and Rook.