Landed from UA 858. Passport control lines extend all the way to the end of the immigration hallway. Since I've landed, it's been down. :20 mins and counting.

Update 1: :30 mins and counting. No announcements, other than what is spreading by passengers from the beginning of the line. Wonder if CBP has a backup plan in cases like this?

Update 2: they just announced that the system has been down since 8:00 am and they are "working on the backup plan." Wow, a backup plan that still isn't in place 3 hours later...

Update 3: About 11:15(?) or so, the systems sprang to life and things began to move again.