The announcement, though planned weeks earlier, came hours after North Korea tested an intercontinental ballistic missile, which flew about 1,000 kilometers before landing in the Sea of Japan.
Hawaii this week will resume monthly statewide testing of Cold War-era nuclear attack warning sirens for the first time in at least a quarter century, in preparation for a possible missile strike from North Korea, state officials said on Tuesday.
A recording of the wailing air-raid siren - familiar to older generations who grew up hearing it on a regular basis - was played at a news conference by Governor David Ige, civil defense and emergency management officers in the state capital, Honolulu.
Ige said he believed Hawaii was the first in the nation to reintroduce statewide nuclear siren drills.
The announcement, though planned weeks earlier, came hours after North Korea's latest test launch of an intercontinental ballistic missile, which flew about 1,000 kilometers (620 miles) before landing in the Sea of Japan. The Pentagon said the rocket posed no danger to the United States, its territories or allies.
But state emergency management authorities said they decided in recent months to reactivate the state's nuclear attack sirens for the first time since the 1980s after experts deemed some of North Korea's missiles were capable of reaching Hawaii.
The wailing air raid sirens - distinguished from steady-tone sirens already in use to warn of hurricanes, tsunamis and other natural disasters - were set to return on Friday.
Both sirens will be sounded in separate 50-second intervals from more than 400 locations across the central Pacific islands starting at 11:45 a.m. in a test that will be repeated on the first business day of each month thereafter.
The exercise is being launched in conjunction with public service announcements urging residents of the islands to "get inside, stay inside and stay tuned" when they hear the warning.
A single 150-kiloton weapon detonated over Pearl Harbor on the main island of Oahu would be expected to kill 18,000 people outright and leave 50,000 to 120,000 others injured across a blast zone several miles wide, state Emergency Management Agency officials have said, citing projections based on assessments of North Korea's nuclear weapons technology.
While casualties of that scale would be unprecedented on US soil, an agency fact sheet stressed that 90 percent of Hawaii's 1.4 million-plus residents would survive "the direct effects of such an explosion."
Oahu, home to a heavy concentration of the US military command structure, as well as Honolulu and about two-thirds of the state's population, is seen as an especially likely target for potential North Korean nuclear aggression against the United States.
In the event of an actual nuclear missile launch at Hawaii from North Korea, the attack sirens would give island residents and tourists just 12 or 13 minutes of warning before impact, according to the state's fact sheet.
In that case, residents are advised to immediately take cover "in a building or other substantial structure." Although no designated nuclear shelters exist, staying indoors offers the best chance of limiting exposure to radioactive fallout.
Calling the North Korea threat a "new normal," Ige said.
"A possibility of attack today is very remote, but we do believe that it's important that we be proactive, that we plan and are prepared for every possibility moving forward."