Here is the final log we received on Amazon for Northern California Data Center:
5:28 PM PST We are investigating network connectivity issues in a single Availability Zone in the US-WEST-1 Region.
6:15 PM PST We continue to investigate network connectivity issues for instances and failures of newly launched instances in a single Availability Zone in the US-WEST-1 Region.
7:09 PM PST We have identified the root cause of the network connectivity issues for instances and failures of newly launched instances in a single Availability Zone in the US-WEST-1 Region. Connectivity to some instances has been restored and we continue to work on the remaining instances.
8:10 PM PST Between 4:52 PM and 7:49 PM PST we experienced network connectivity issues for instances and failures of newly launched instances in a single Availability Zone in the US-WEST-1 Region. The issue has been resolved and the service is operating normally.
We are having a meeting today with our Amazon AWS representative to discuss the cause for this problem, and how we can best avoid being impact by such an outage in the future.