Many people caught in the storm were imbued with superpowers. It is important to note that not everyone in the presence of the storm were given superpowers, it seems most likely that only those struck by lightning or very close to a lightning strike were given powers.
The powers were diverse and often not your conventional superpowers. The manifested powers often reflected the person's own insecurities and self awareness; a shy social outcast who everyone ignores is given the power of invisibility, or a person who appears selfish, manipulative, and unsustainable on the surface can now duplicate into a second person who is their true polarized personality. In this way, the powers could grant people's deepest desires, (i.e. to become a rocket scientist) or surround them with their deepest fears... The storm gives powers like this. As for the metorite my understanding for that is that the metagene is opportunistic.