Launched from Cape Canaveral due East. A pilot flying over Sudan reported seeing a spiral cloud that may have been the upper stage dumping fuel prior to re-entry, and an anonymous gov official allegedly claimed it burnt up over the Indian Ocean. Interestingly, US authorities have or will not officially confirm the success or failure of the launch.

"The US government has not publicly stated if there was a failure of Zuma, and this secrecy has generated speculations on its purpose and its fate. A number of articles published by the amateur satellite tracking community stated that if the satellite was still in orbit or operating covertly, then it would likely be located visually. In the process of searching for Zuma, amateur astronomers instead found radio transmissions from IMAGE, a NASA satellite that was lost in 2005."

Probably not related, but it got my inner conspiracy speculator going. Maybe nothing, maybe the launch failure was a cover, maybe the spy satellite was really a weapons platform, maybe someone else intercepted it over Hawaii causing the alert. I'd wager if 9/11 had been thwarted at the last minute it would be remembered about as well as the Hawaii ballistic missile alarm.

On a less conspiratorial note, it's hard to imagine an entire state suddenly being told their world is about to end in 20 minutes. I have no idea what I would actually do in that situation, but the people of Hawaii, for better or worse, certainly do now. I think it would have to be on most peoples short list of most profound life experiences.