In the final days of the Mage Wars, the Archmage Urtho was betrayed by one of his generals, Shaiknam, who sent a traitorous mage to assassinate him. The mage, Conn Levas, did succeed in fatally poisoning Urtho. Urtho had trapped his Tower and Gate network, to explode upon his death. He had hoped to use it as a final weapon against Ma'ar. With his death imminent, Urtho sent Skandranon off with a magical device to eliminate Ma'ar and his magic. He also completed the evacuation of his people and armies.
When Skandranon set off the device in the throne room of the Royal Palace of Tantara, Ma'ar's current headquarters, Ma'ar's set spells were destroyed causing waves of destructive magic to move outward like ripples on a pond. Urtho's nearly simultaneous death, and the subsequent destruction of his magical network moments later caused a second set of waves, crashing into the first set. The explosions resulted in two massive craters where the palace and Tower once stood, which later became Lake Evendim and the Dhorisha Plains, respectively. The ripples of wild magic crashing into each other twisted the land between the two locations, forming the weirdness of the Pelagirs.
The explosion caused ripples in the magic fields of the land, prompting what came to be called the Mage Storms. The destruction and havoc caused the collapse of magic-dependent civilizations far beyond the lands Ma'ar had controlled.
Thousands of years later, these waves echoed back over Velgarth in a second set of Mage Storms.