I also checked my UCI status page today, and it also has the words "on hold" next to alternate. (I interviewed in late Jan.) From what I read in this thread, this is what I understand "on hold" next to "alternate" at UCI to mean - if this is actually wrong, someone please correct me.
-- Having the words "on hold" next to "alternate" means your application is currently under review (post-interview). Once this review is completed, one of these two things can happen:
1) The "On hold" next to alternate changes to "yes" - this means you are now on the wait list. There is little movement off the wait list until June; on some years a lot of people are taken off the wait list, on some years, only a few.
2) The "On hold" next to alternate disappears - and is replaced by a date next to "Final Decision Letter." This can mean either a letter of rejection, or a letter of acceptance will soon be mailed to you. Some acceptances are accompanied by phone calls from the administration. Also, the period of time for "on hold" to change can take anywhere from a few days to a couple weeks.
Again, if my understanding of any of this is wrong, someone please let correct me, because I'd really like to know what this "on hold' stuff really means. Thanks. 🙂