If the alum board is aware of the situation, and the officers in question have broadcasted their partying/drinking on "FB, Twitter, and to anyone else who will listen," where are the advisors? Are they aware? Or am I confused and by alum board you mean the advisory board?

Yes, I meant it the way angels&angels explained it. Normally they don't vote at all because it turns into a campaign trying to win over the new members.

Yes the alum board are the advisors. We are an extremely small sorority.

Thanks for everyone's help so far!! We decided to take her to standards.

Taking her to standards was a very good choice. The president doesn't have to be perfect, but that is not how a president should behave. It's possible that if she is held accountable, you may have to elect a new president (if that is within your sorority's bylaws). No member of any sorority should have that kind of behavior, it looks bad on the entire chapter when just one member (particularly the president) acts in such a manner. I haven't heard of a sorority that doesn't have an alcohol risk management program, and this violates alcohol safety and shows a huge amount of disrespect for the sorority.

question! are local sororities supposed to have a risk management program?

If it's a local, it's completely up to the rules they set when they first organized. If they didn't form a standards board, or judicial branch, or something like it, they there isn't one.
Seems like the school would require that of any organization.