The guided-missile submarines USS Ohio and USS Michigan are based at Naval Base Kitsap, but operate out of Guam, which North Korea this week threatened to ring with missiles.
They are two of the Navy's four former nuclear-missile submarines converted a decade ago to carry out land strikes with up to 154 Tomahawk cruise missiles and 66 special operations forces. The others are USS Florida and USS Georgia at Naval Submarine Base Kings Bay, Georgia.
The Ohio and Michigan, each with separate blue and gold crews, are forward-deployed to Naval Base Guam for about a year at a time to be closer to potential hostilities.
Between 3 to 4-month patrols, the subs return to the island and swap out crews. The boat stays put while sailors fly back and forth from Washington.
After about 12 months, one submarine returns to Puget Sound Naval Shipyard for maintenance and the other takes its place.
Eight other Naval Base Kitsap submarines rarely are seen in Guam. They operate directly out of Bangor, remaining hidden under the waves, armed with nuclear missiles.
Carrying out such a mission, they don't typically enter a port. Called "boomers," their mission is to deter a first-strike attack through their ability to survive.
One boomer did pull into Guam's Apra Harbor last Oct. 31. The USS Pennsylvania made a port visit to demonstrate the United States' commitment to its allies in the Pacific.
Naval Base Guam supports the Navy's entire 7th Fleet, which covers the western Pacific and Indian oceans. It has four Los Angeles-class fast attack submarines of its own — USS Oklahoma City, USS Chicago, USS Key West and USS Topeka — and sub tenders USS Emory S. Land and USS Frank Cable.
The 30-mile-long island became part of the world's biggest news story this week in blustery threats between President Trump and North Korean leader Kim Jong-un.
Trump warned on Tuesday that if North Korea continued to threaten the U.S., he would unleash "fire and fury" on the country. Defense Secretary Jim Mattis, visiting Bangor on Wednesday, issued a statement that North Korea shouldn't consider actions that would "lead to the end of its regime and the destruction of its people."
On Thursday, Kim vowed to ignite an "enveloping fire" of test missiles near Guam. North Korea said it is finalizing a plan to fire four of its Hwasong-12 missiles over Japan and into waters around the tiny island, which hosts 7,000 U.S. military personnel and has a population of 160,000. It said the plan, which involves the missiles hitting waters 19 to 25 miles from the island, could be sent to Kim for approval within a week or so. It would be up to him whether the move is actually carried out.
Trump responded to North Korea's threat with a threat of his own.
"Let's see what he does with Guam," Trump said. "He does something in Guam, it will be an event the likes of which nobody has seen before."