Twelve Marines remained missing Friday off Oahu’s North Shore, where military and civilian agencies battled high seas in search of possible survivors and debris from two Kaneohe-based choppers.

Thursday’s late-night crash led to a daylong search in dangerous waters off Haleiwa under cloudy skies, where monster surf was forecast to peak Friday night and waves were expected to remain high today.

There had been no sign of survivors, and Marines are investigating the cause of the crash.

Two Navy warships, the Coast Guard cutters Ahi and Kiska, an MH-65 Dolphin helicopter and a C-130 Hercules planned to continue searching through the night.

The two CH-53E Super Stallion helicopters, on a “routine training” mission and each carrying six Marines, may have collided before crashing into the ocean at about 10:40 p.m. Witnesses described hearing a loud crash and explosions.

The Coast Guard did not receive a mayday call, said Coast Guard Lt. Scott Carr at a press conference Friday afternoon at Marine Corps Base Hawaii at Kaneohe Bay, where the helicopters were based. “The Coast Guard was notified by a civilian on the beach who had seen the aircraft flying and then saw them disappear … (saw) a fireball and then notified the Coast Guard,” Carr said. The call came at 11:38 p.m., he said.

North Shore residents reported hearing loud explosions, and the Honolulu Fire Department said it dispatched crews at 10:52 p.m.

Haleiwa resident Mark Waugh, 42, said he was going to bed “about 11-ish” when he heard the sound of helicopters and “a big boom. It was very loud.” He said two friends who live on the shoreline also heard the crash.

Waugh, a North Shore surfer, plumber and former Army specialist, called Friday’s wave conditions “extreme monster surf.”

“God bless the troops,” Waugh added.

Families hold out hope

Capt. Tim Irish, Marine Corps Base Hawaii spokesman, said the Thursday night flights were “part of routine training” and that the helicopters were scheduled to return to the base. He said that the two helicopters didn’t check in on time and were reported missing. “So we started working with the Coast Guard as the first responders.

“It was aircrew; there were no passengers on board,” Irish continued. He said the crew is normally four. “I have heard that there were one or two additional instructor-trainers aboard,” he said.

“There are several Marine Corps families affected right now, and they’ve got a lot of concern for their loved ones, and our hearts and prayers definitely go out to them as well, as part of our family,” Irish said.

The identities of the missing had not been released Friday, but the family of Capt. Kevin Roche said he was in one of the helicopters, and indicated during the day they were holding out hope as the search continued. “We believe the Marines and Coast Guard are doing everything they can to bring Kevin and his fellow Marines home safely, and we are grateful to everyone involved in the rescue,” said a family statement distributed by brother-in-law Anthony Kuenzel in St. Louis.

An aunt posted on a Marine Corps Facebook page that three Marines visited Roche’s parents and reported that he was missing.

Debris found offshore

Debris from the crash was sighted 2.5 miles off Haleiwa shortly after midnight, Coast Guard officials said. Carr said two life rafts were found in the search area — one inflated and one not.

Crews were searching a debris field spread out over about seven miles offshore, from Mokuleia Beach to Turtle Bay, according to the Coast Guard. The water depth varies from 156 to 1,400 feet between the half-mile and 7-mile marks in the area.

The Coast Guard established a safety zone from Kaena Point to Kahuku Point from the shoreline to 8 miles out in the ocean.

“We have found debris across that entire area,” Carr said. “We have seen debris, haven’t recovered any of it. But the debris is consistent with military aircraft.”

Carr said because of the extremely dangerous high surf conditions on the North Shore, both surfers and beachgoers should exercise caution in the area.

He said the debris could potentially cause serious harm. “Even if anyone sees debris in the water,” Carr said, “they should not try to retrieve, but call the Coast Guard.”

Police have asked the public not to touch any debris that may be found on the shore between Haleiwa and Kahuku. People are advised to instead call the Coast Guard at 535-3333, according to Irish.

Multi-agency search

Several agencies were helping to conduct the search and investigation.

Irish said 30 Marines from Marine Corps Base Hawaii were on the scene assisting with the search efforts and that more would be sent along with barrels to collect crash debris. A Marine MH-60 helicopter crew from the 37th Helicopter Squadron out of Kaneohe assisted in the search.

Joining in the search were two Pearl Harbor-based destroyers — the USS John Paul Jones and USS Gridley — and a Navy helicopter from Kaneohe Bay.

A Honolulu Fire Department spokesman said at least six of its units and its helicopter and rescue boat were searching, and crews had set up their command at Haleiwa Small Boat Harbor.

The Coast Guard said a MH-65 Dolphin helicopter and HC-130 Hercules aircraft were dispatched from Barbers Point and arrived on scene just after midnight and spotted the debris field.

Two Coast Guard rescue boats — the 110-foot patrol boat Kiska from Hilo and the 87-foot patrol boat Ahi from Maui — joined the search, as did a Navy MH-60 helicopter from Kaneohe Bay.

Sound of explosions

Shanee Giltner-Baptiste, 45, who lives in a home across from Haleiwa Alii Beach Park, said she heard the sound of helicopters at about 10:40 p.m. and then two loud explosions. “I thought it was a Schofield bombing; it was so strong,” she said.

The “booms” rattled her home twice, she said. Within moments she heard emergency responders and could hear talk on their radio chatter about 12 people onboard.

Burt Sutherland, 59, of Pupukea said he was using his computer shortly before 11 p.m. when he heard “two smacking, kind of banging-smacking sounds.” He too thought is was artillery from Schofield Barracks.

He said it was so loud he went up to his lanai to investigate. “There was no moon, no light. It was misty and raining,” Sutherland said.

He said military helicopters had been flying over the area for much of Thursday afternoon at an elevation that he estimated to be about 1,000 feet.

The CH-53E Super Stallion’s mission is the transportation of heavy equipment and supplies for amphibious assault. The Navy said there are currently 151 CH-53E aircraft in operation. The two helicopters were from the Marine Heavy Helicopter Squadron 463 of the 1st Marine Aircraft Wing.