Not sure what I will do...

So I have this friend from college who basically kept something of medium importance from me for about a year, finally told me after about five months of ignoring me, made a big stink and whined about petty stuff, and ignored me when I tried to engage her with polite questions concerning her motives for not talking to me sooner.

Since we go to a really small college and are basically in the same building for most classes, I have a sneaking suspicion that she and I will run into each other this year. I'm not quite sure what I will do. I know what I*should* do, which is to be cordial and keep conversation honest yet simple, since her + dramatic overreactions= scary. I've seen her go off on other people, and I seriously do not want to incur her wrath. I just want to stay as far away as possible, but that's kind of difficult at a college as small as ours.

I guess what I mean to say is, do you guys have any advice? Has something like this happened to you? How did/would you handle confronting a former friend like this? Were you ever able to make amends, or did you find that avoidance was the better route to take?