Well, you need to a)read the thread title. And b)understand that these events can be very local if they involve the lower proton belt if the Van Allen radiation belts coming in contact with the Earths surface.

No one even knows what caused this, I'm not sure myself. There was a dramatic drop in electron flux followed by an almost complete failure of the geomagnetic field last night though. Remember, electrons in the solar wind are what powers the earth protective shield. The solar wind almost completely subsided.