OK, so I'm currently reading a horror book called Snowblind by Christopher Golden and I'm not really sure what to call his style of writing. Essentially, it's about a group of people facing a supernatural blizzard (well, more like there's a spirit/ghost/demon inside the blizzard, I'm still in the first chapter) much like the one that claimed their loved ones twelve years ago. Well, he spends four chapters (I checked) in the past building up the horrors of the first blizzard before jumping forward to modern times where the actual story begins. Effectively, you could almost interpret those four chapters to be the 'prologue'. It also doesn't help that the blurb on the front cover flap pretty much spoils the first four chapters by revealing who lived and who died during the first blizzard. I'm also reminded of another supernatural horror book I read (of which I can't remember the name of now, sadly) where it jumped back and forth between 1914 and present times. My question is, what would you call this style of writing? Is it normal in supernatural horror novels to spend some time in the past before jumping forward in the present, or to jump back and forth between the past and the present? Why do some authors choose to do this? Doesn't it disrupt the flow of the story? Thoughts?