There was this butterfly that can flap it wings in one part of the world and start hurricanes in another part. (But it doesn't guide them ... sorry about that.) And there was also an aeons old magical artifact that had become partially exposed due to erosion and excavation for construction, a meteorite composed of materials not found on earth that had absorbed strange cosmic energies when it was still in space, and a massive blue lightning bolt.
I just happened to be have stopped nearby to look at the butterfly, which was sitting on an exposed part of the magical artifact. The meteorite struck that part at the same time that the lightning bolt did.
The resulting outburst of energies gave me my powers.