Starting in November, Hawaii residents statewide will hear an air raid warning siren test that’s not been heard since the Cold War — a wailing alert that potentially would be used to warn of a North Korean missile attack.

The new siren — which differs from the more familiar “attention alert” steady sound for threats such as hurricanes or tsunamis — is part of a new state of Hawaii preparedness and information campaign aimed at addressing the growing North Korean threat.

That threat level — potentially delivering the destructive force of the bomb dropped on Hiroshima in 1945 — has ushered back in some 1950s-era practices that would be pointless with the megaton yields of today’s Russian and Chinese nukes, officials say.

Elements of the plan were detailed today by the Hawaii Emergency Management Agency, which is attempting to walk a tough line between preparing the state for the unlikely event of a North Korean intercontinental ballistic missile attack, and not causing unnecessary alarm in a state dependent on tourism.

“We do not want to cause any undue stress for the public; however, we have a responsibility to plan for all hazards. We don’t know the exact capabilities or intentions of the North Korean government, but there is clear evidence that it is trying to develop ballistic missiles that could conceivably one day reach our state. Therefore, we cannot wait to begin our public information campaign to ensure that Hawaii residents will know what to do if such an event occurs,” Vern Miyagi, state Emergency Management Agency administrator, said in a release Thursday.

Miyagi said today that “the question comes up — why now?” with the preparedness plan, even though the threat level is low. However, Hawaii residents repeatedly ask, “What is Hawaii doing?” Miyagi said.

Lt. Col. Chuck Anthony, a state Department of Defense spokesman, said, “We’ve been told that every single town hall that (Gov. David Ige) holds, the question comes up about what Hawaii is doing” about North Korea’s capabilities.

The wailing siren that will be tested in November actually harks back to World War II air raid sirens used in Hawaii, said Toby Clairmont, executive officer for Hawaii Emergency Management.

“That capability has been in our state for all these years, but we haven’t had to use it,” Clairmont said. The air raid siren will be tested to see how well it is differentiated from the regular “attention alert” siren.

“So we need to start getting people thinking about this, because we are going to be triggering these sirens in November,” Clairmont said.

State officials are postulating a possible 15-kiloton North Korean nuclear device detonated 1,000 feet above Honolulu, which would be survivable for the vast majority of the state’s residents. For comparison, the bomb dropped on Hiroshima in 1945 also was 15 kilotons.

The state plans to run public service announcements and provide other information that stresses immediately seeking shelter in a building, preferably with thick concrete, in the event of an attack.