The North Korean nuclear threat will soon enter Hawaii living rooms a little more forcefully as the state adds an “attack warning” wavering-tone siren to its monthly “attention alert” tests for hurricanes, tsunamis and earthquakes.

At 11:45 a.m. Dec. 1, during regular siren tests on the first business day of each month, 50 seconds of the steady-tone alert will be followed by a pause and then 50 seconds of the attack warning tone, said Hawaii Emergency Management Agency Executive Officer Toby Clairmont.

Clairmont said the last time Hawaii residents heard the attack warning siren test was around 1980 during the Cold War. The siren, if used as an actual warning, would signal the need to immediately seek shelter.

The Russian threat, now far more removed, has been replaced by the unpredictability of North Korea, which exploded a nuclear device Sept. 3 that may have had yielded 250 kilotons or more. By comparison, the Hiroshima blast was about 15 kilotons.

For the foreseeable future, the additional monthly attack warning sirens will be the new norm statewide. Hawaii Emergency Management unveiled a sample of the wavering siren at a preparedness presentation Saturday and in a new public service announcement now running.

President Donald Trump said Tuesday in Seoul that it “makes sense for North Korea to come to the table and to make a deal” — presumably to halt its nuclear program.

He preceded that saying, “We sent three of the largest aircraft carriers in the world (to the region), and they’re right now positioned. We have a nuclear submarine also positioned. We have many things happening that we hope … in fact, I’ll go a step further, we hope to God we never have to use.”

At home, Hawaii officials continue to battle misconceptions over the nuclear preparedness planning. Officials say an attack on Hawaii is very unlikely but also can’t be ignored.

“As Hawaii prepared for this over the last couple of months, we’ve been getting inquiries from other states, working with Guam also, but (also), ‘What are you guys doing? Why are you doing this?’” Hawaii Emergency Management Administrator Vern Miyagi said during the presentation Saturday. “And like I said, this is because there was an elephant in the room, and we have to address it.”

Hawaii, one of the first states to initiate a nuclear preparedness campaign, was previously depicted as a target by North Korea, and Oahu is home to the Navy’s U.S. Pacific Command. The state also is a lot closer than most to the volatile North.

For planning purposes, the state is theorizing a 150-kiloton-yield bomb detonated over Joint Base Pearl Harbor-Hickam, which it said Saturday would cause nearly 18,000 fatalities and 50,000 to 120,000 trauma and burn casualties.

Fifteen to 30 percent of survivors exposed to initial radiation or fallout would experience acute radiation sickness in the affected target area. Severe damage would be caused to Daniel K. Inouye International Airport and the harbor, and power and water would be out.

But even all that would be survivable by the vast majority of Hawaii’s more than 1.4 million residents, officials say.

“As far as casualties (from a North Korean strike), we’re talking about maybe 10 percent,” Miyagi said. “It’s not pretty. … So when it impacts, and 10 percent casualties, (you have) 90 percent survivors.”

Miyagi said the state has weekly teleconferences with the Department of Homeland Security, working with the Federal Emergency Management Agency, “talking about how we are advancing our plans with respect to the post-impact (environment), and how that’s going to work.”

Miyagi also said it’s unlikely Hawaii would be targeted by North Korea, for a variety of reasons, including that leader Kim Jong Un is not crazy and that any launch against the United States or its allies would be suicide. North Korea also has yet to prove it has mastered telemetry and warhead re-entry issues.

“He has a limited amount of missiles, and there are many, many closer-in targets that he is guaranteed of hitting, such as Japan and South Korea and even the continental United States. If he heads it that way, he’ll hit something,” Miyagi said. “Hawaii is a very tiny target. Even Guam. Guam is a very tiny target for him.”