frankthedm said:No, a line has to pass through a square to affect it.
I'll post supporting info once I find it, but I don't believe that to be the case.
I'm fairly certain that the current ruling is that if a line traverses the edge of a square it is considered to pass through that square and thus affects that square. Thus a Lightning Bolt can affect a 10'x10'x120' area if fired down a gridline.
The other interpretation would be that a Lightning Bolt fired down a gridline affects no squares, which doesn't seem to make a lot of sense to me.