Possible legal trouble for causing mass hysteria

I am wondering... I am a fairly seasoned prankster (none of my pranks have caused harm, physical or psychological), and it is always taken in jest. I have come up with a hoax that is somewhat similar to the one Orson Wells did with his reading of 'War of the Worlds'.

What possible legal ramnifications could become of this? Granted, there is no terrorist, nor the threat of harm coming to people, but I can't seem to find any law against causing mass panic. (Yes, yes, I know, the whole thing in Boston can be seen as one that easily could land those two lads in jail, but there is no joke of bombs or attacks with my idea.)

Where can I find legal documents online regarding my situation?

If there is any reasonable expectation it could cause panic you will be liable...that is the law.

Granted, but 'panic' is one of those things where it is tricky to prosecute someone for causing. I had a friend growing up that panicked at the site of rain. Does that mean that one day, if we're driving for a few hours, it starts raining, I can be arrested for putting someone in an extended state of panic?

I doubt rain will send you to jail??