Shortly after 8 am local time on Saturday morning, an employee at the Hawaii Emergency Management Agency settled in at the start of his shift.
Among his duties that day was to initiate an internal test of the emergency missile warning system: essentially, to practice sending an emergency alert to the public without actually sending it to the public.
It was a drill the agency had started with some regularity last November - around the time Hawaii reinstated its Cold War-era nuclear warning sirens amid growing fears of an attack by North Korea - and so, while the tests were not yet routine enough to be predictable, they were not entirely new either, according to an agency spokesman.
Around 8.05 am, the Hawaii emergency employee initiated the internal test, according to a timeline released by the state. From a drop-down menu on a computer program, he saw two options: "Test missile alert" and "Missile alert". He was supposed to choose the former; as much of the world now knows, he chose the latter, an initiation of a real-life missile alert.
"In this case, the operator selected the wrong menu option," HEMA spokesman Richard Rapoza told the Washington Post.
Around 8.07 am, an errant alert went out to scores of Hawaii residents and tourists on their cellphones: "BALLISTIC MISSILE THREAT INBOUND TO HAWAII. SEEK IMMEDIATE SHELTER. THIS IS NOT A DRILL." A more detailed message scrolled across television screens in Hawaii, suggesting, "If you are indoors, stay indoors. If you are outdoors, seek immediate shelter in a building. Remain indoors well away from windows. If you are driving, pull safely to the side of the road and seek shelter in a building or lay on the floor."
The false warning sparked a wave of panic as thousands of people, many assuming they had only minutes to live, scrambled to seek shelter and say their final goodbyes to loved ones. The situation was exacerbated by a 38-minute gap between the initial alert and a subsequent wireless alert stating the missile warning was a mistake.
8:05 a.m. — Workers initiate routine test of the emergency alert system.
8:07 a.m. — A worker mistakenly hits the button to send the emergency warning reading: "BALLISTIC MISSILE THREAT INBOUND TO HAWAII. SEEK IMMEDIATE SHELTER. THIS IS NOT A DRILL."
8:10 a.m. — The head of the Emergency Management Agency, state adjutant general Maj. Gen. Joe Logan, confirms with U.S. Pacific Command that there was no missile launch. Honolulu police are notified of the false alarm.
8:13 a.m. — The state issues a cancellation that prevents the message from being sent to phones that hadn't previously received, such as those out of cellphone coverage range or who had phones turned off.
8:20 a.m. — The Emergency Management Agency issues public notification of cancellation on Facebook and Twitter.
8:24 a.m. — Gov. David Ige retweets the cancellation notice.
8:30 a.m. — Ige posts cancellation notice on his Facebook page.
8:45 a.m. — Cancellation of warning sent to cell phones: "There is no missile threat or danger to the State of Hawaii. Repeat. False Alarm." The state said it issued the cancellation after getting authorization to do so from the Federal Emergency Management Agency.
Hours afterward, Hawaii Governor David Ige, (D), apologised for the "pain and confusion" the wayward alert had caused and said it had been "a mistake made during a standard procedure at the changeover of a shift and an employee pushed the wrong button".
But one day after the debacle, more details are emerging about how such a mistake occurred, amid growing calls for accountability and for a close re-examination of the wireless emergency alert system.
US Federal Communications Commission Chairman Ajit Pai called the false alert "absolutely unacceptable" and said a full investigation was "well underway". At least initially, Pai seemed to cast blame on state-level officials for the error.
"Based on the information we have collected so far, it appears that the government of Hawaii did not have reasonable safeguards or process controls in place to prevent the transmission of a false alert," Pai said.
"Federal, state, and local officials throughout the country need to work together to identify any vulnerabilities to false alerts and do what's necessary to fix them. We also must ensure that corrections are issued immediately in the event that a false alert does go out."
Pai did not elaborate on what safeguards or process controls were lacking in Hawaii that might typically be in place elsewhere. Wireless emergency alerts are dispatched during critical emergency situations - to warn the public of dangerous weather, missing children and security threats - and are a partnership of the FCC, FEMA and the wireless industry. While the FCC establishes rules and regulations surrounding emergency alerting, responsibility for sending those messages typically falls to emergency management officials.
Part of what worsened the situation was that there was no system in place at the state emergency agency for correcting the error, Rapoza said. The state agency had standing permission through FEMA to use civil warning systems to send out the missile alert - but not to send out a subsequent false alarm alert, he said.
Though the Hawaii Emergency Management Agency posted a follow-up tweet at 8.20 am saying there was "NO missile threat," it wouldn't be until 8.45 am that a subsequent cellphone alert was sent telling people to stand down.
"We had to double back and work with FEMA (to craft the false alarm alert) and that's what took time," Rapoza said.
That has since been remedied, he said, with a cancellation option that can be triggered within seconds of a mistake.
"In the past there was no cancellation button. There was no false alarm button at all," Rapoza said. "Now there is a command to issue a message immediately that goes over on the same system saying 'It's a false alarm. Please disregard.' as soon as the mistake is identified."
The Hawaii Emergency Management Agency said it has also suspended all internal drills until the investigation is completed. In addition, it has put in place a "two-person activation/verification rule" for tests and actual missile launch notifications. Rapoza said that at the weekend, the employee was asked in the computer program to confirm that he wanted to send the message. In the future, a second person will be required for confirmation.
The agency said it would issue a preliminary report of findings and corrective actions next week. The employee in question has been temporarily reassigned, Rapoza said, but there are no plans to fire him.
"Part of the problem was it was too easy - for anyone - to make such a big mistake," Rapoza said. "We have to make sure that we're not looking for retribution but we should be fixing the problems in the system. ... I know that it's a very, very difficult situation for him."
The errant alert had sparked angry responses by state and federal officials for more accountability over the emergency alert system. Hawaii Senator Brian Schatz, (D), blasted the false alarm as "totally inexcusable" and called for the process to be fixed.
"This system failed miserably and we need to start over," Schatz tweeted. Today he indicated he would be open to drafting legislation to change the notification system if necessary.
Other Hawaii leaders focused not on the alert system but on the growing tensions between the United States and North Korea that had fuelled fears of a nuclear strike in the first place. On CNN's State of the Union, Representative Tulsi Gabbard, (D), criticised President Donald Trump for not taking the threat of nuclear war seriously enough and urged him to engage North Korean leaders in serious negotiations to denuclearise.
The mistaken alert was sent while the President was at Trump International Golf Club near his holiday home in Palm Beach, Florida, although it was not clear whether he was on the golf course at the time.
A White House official said Trump was quickly briefed by deputy national security adviser Ricky Waddell, who accompanied Trump from Washington. He later discussed the episode with National Security Adviser H.R. McMaster and White House Chief of Staff John F. Kelly, the official said.
The federal Government keeps track of North Korean launches through several means, including satellite surveillance, and officials around Trump would have known that no missile was detected.
Trump was not seen in public and he issued no statements about the incident.
The only public mention of the incident came from deputy White House Press Secretary Lindsay Walters, who made clear that the federal Government was not involved.
"The President has been briefed on the state of Hawaii's emergency management exercise. This was purely a state exercise," Walters said.
Walters also accompanied Trump to Florida.
While there is no protocol that applies directly to such a mistake, past presidents have often weighed in to reassure the public at times of stress or threat.