Authorities held a secret meeting last week to discuss contingency plans in the event of Pyongyang launching a deadly missile at the US islands.
North Korean dictator Kim Jong-un has threatened to drop a hydrogen bomb over the Pacific Ocean amid fears Pyongyang has developed a nuclear missile capable of reaching Hawaii.
A document shared at the private talks, and obtained by local paper Honolulu Civil Beat, featured chapter headings such as “Enhance missile launch notification process between U.S. Pacific Command and the State Warning Point.”
The US state, in the middle of the Pacific Ocean, will also begin testing a warning siren system in November, giving residents between 12 and 15 minutes to take refuge.
Resident wil then be advised to stay indoors for 72 hours after an attack.
State representative Gene Ward told the Washington Post: “Now it’s time to take it seriously.”
He said the plan was “not to be an alarmist but to be informing people.”
Mr Ward said the meeting last week was held in private because officials did not want to worry residents.
He also said talk of bunkers and fallout shelters was “probably more surreal for younger generations” with no experience of a realistic nuclear threat.
But Hawaiians are apparently taking the news in their stride, and carrying on with their daily lives.
Residents are used to disaster warnings, living in an area prone to hurricanes and tsunamis.
Survival guidelines for those scenarios are similar to the ones being issued for a nuclear attack – instead of seven days worth of food, water and medical supplies, residents are advised to double it.
The document distrubted at last week’s meeting suggested that around 90 per cent of the Hawaiian population would survive a nuclear attack by North Korea, based on the estimated yield of North Korea’s missile capability, which suggests an explosion less than eight miles in diameter.
It comes as America’s top military officer said despite an escalation in rhetoric between the US and North Korea, he had not seen Pyongyang change it’s military posture.
Marine General Joseph Dunford, chairman of the military’s Joint Chiefs of Staff, told a Senate Armed Services Committee hearing for his reappointment: “While the political space is clearly very charged right now, we haven’t seen a change in the posture of North Korean forces and we watch that very closely.
“What we haven’t seen is military activity that would be reflective of the charged political environment.”
North Korea has boosted defences on its east coast, a South Korean lawmaker said on Tuesday, after Pyongyang said US President Donald Trump had declared war and that it would shoot down US bombers flying near the peninsula.
Tensions have escalated since reclusive North Korea conducted its sixth and most powerful nuclear test on Sept. 3. Bellicose rhetoric has reached a new level in recent days with leaders on both sides exchanging threats and insults.
North Korean Foreign Minister Ri Yong Ho said on Monday that Mr Trump’s Twitter comments that leader Kim Jong Un and Ri “won’t be around much longer” if they acted on their threats amounted to a declaration of war and that Pyongyang had the right to take countermeasures.