It came back up about 20 minutes later - this is the response I got from support: "The brief outage today was due to unplanned maintenance in response to an issue that our cloud team is actively investigating. One of our support team members will reach out if anything from that investigation indicates that we should take cooperative action or address any issues specific to your instance."
My issue is with the word "if." I think we deserve an explanation regardless of the outcome of the investigation. We should be told what is being put in place to keep this from happening again.