This will be our origin event. You’re at (or near, if you already have powers) the Occupy Steel City rally, and after we set our locations… (From the Emerald City sourcebook)
“The loud, heart-stopping sounds of an explosion and shattering glass along with the accompanying shock strike you all without warning. Within moments, a strange cloud of silvery mist blankets the surrounding area. Just as panic and flight are about to take hold, the cloud begins to swirl without any evident prompting from the wind. It whips itself into a cyclonic mass, discharging what appear to be bolts of bluish lighting both within itself and outward around its immediate vicinity.”
And an eyewitness account of the Silver Storm, and the one that provided the name:
“With the metallic clouds rushing out and those weird bolts of blue-white lightning and that howling wind, it was like some kind of silver storm.”
An unknown number of people died or got superpowers through the Silver Storm event: though dozens died or were injured, and there are still over 120 people in chrysalises from the event, an unknown number of people just walked away from the event with powers. Others did not get powers.
Anyone actually hit by a bolt of lightning got powers, but not everyone in a chrysalis was hit.
Those whose job is threat assessment suspect that between 300 – 1000 people got powers. (Izzy might be able to relay information from her dad, once she (a) talks to him and (b) he decides to tell her and if ( c) he is allowed to tell her. (Currently he doesn’t know she was involved in any way — it’s another country, for goodness’ sake.)
Two of the PCs saw that a Hightecker van was stopped, exploded, and then the silvery storm came from the wreckage (though after the explosion, you couldn’t make out the corporate name any more).