Oly720man From United Kingdom, joined May 2004, 6517 posts, RR: 11 Reply 2, posted (7 years 10 months 4 weeks 2 hours ago) and read 2339 times:
Having read Bill Bryson's book about nearly everything, you have to be at least 10 light years away from it otherwise you'd be toast, and second you'd never know it was going to happen until it suddenly went very bright one day. Then it would be too late.
If you did want to prepare for it then I'd imagine that if there were enough particles to create a meaningful supply of energy you'd be cooked anyway. Ideally the magnetosphere at the top of the atmosphere would deflect any particles to the poles. Great auroras though.