Passengers aboard an Air Canada flight that was forced to divert to Honolulu on Thursday described violent and sudden turbulence that led to terrifying moments in the plane’s cabin, leaving nine with serious injuries and dozens battered and bruised.

“Anybody who didn’t have their seat belts on flew out of their seats,” said Australia resident Vanessa Say.

Say was among 37 passengers and crew members injured on Air Canada Flight 33 from Vancouver, British Columbia, when it was slammed by turbulence without warning en route to Sydney.

“Before anyone had a chance to buckle up, we just plummeted through the air. … It was like being on a roller coaster, that dropping feeling in your stomach,” Say said.

The 777-200 aircraft was traveling at 36,000 feet and approximately 600 miles southwest of Honolulu when it hit turbulence, according to Federal Aviation Administration spokesman Ian Gregor.

>> Photo Gallery: Air Canada flight diverts to Hawaii after turbulence injuries

An Air Canada spokeswoman said 269 passengers and 15 crew members were aboard. The flight diverted to Honolulu and landed safely at Daniel K. Inouye International Airport at 6:45 a.m. Thursday.

More than 50 emergency responders from federal, state, city and private entities that included multiple ambulances and an “ambu-bus” converged at the airport to tend to the injured.

Based on preliminary information, 21 people suffered minor injuries and nine were seriously injured, said Honolulu Emergency Medical Serv­ices Chief Dean Nakano during a Thursday afternoon briefing at the airport.

“We had several patients with neck and back injuries, some with lacerations to the head, some head injuries,” Nakano said. “The ages ranged from children to the elderly.” The youngest patient was a toddler.

Thirty people were taken to various hospitals, and seven refused to be transported. Five crew members were among the injured.

Passengers described “a giant drop.”

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Say, who was seated in Row 40, said she was sleeping when she felt light turbulence. Soon afterward the seat-belt lights illuminated, but the plummet came before there was a chance to buckle up.

She said she struck her head on the luggage compartment, breaking it. “There was a big hole above me,” Say said. “Lots of people hit the cabin ceiling and suffered head injuries. … There was a lot of people bleeding.”

The oxygen masks in the cabin dropped down.

Once the plane stabilized after the single, abrupt drop, crew and passengers scrambled to help one another. One passenger recalled a crew member holding an ice pack to his face as he checked on passengers.

“I think a lot of people were in shock,” Say said as she sat on a concrete bench at the Honolulu airport wearing a neck brace.

Sometime after the turbulence subsided, the pilot called on anyone aboard with medical experience to assist injured passengers. “There (were) plenty of doctors and EMTs and people in training, so they came up and started fixing up people as best as they could,” Say said.

The pilot informed passengers they were heading to Hawaii to get medical attention for injured passengers.

Say’s best friend, whose head was slammed against the air vent and light panel, received three stitches or staples for her head wound.

Another passenger, Lachlan Coffey, described the turbulence as horrifying. He and four fellow band members of Hurricane Fall, a country-rock band in Australia, were seated in Rows 42 and 43.

“It was like a giant drop,” said band member Tim Tricky.

Pepper Deroy, the sole band member who sustained injuries in the turbulence, was sleeping when he was jolted into the air and his right arm struck the armrest on his way down, causing nerve damage to his forearm and elbow. Emergency responders treated him and took him to Pali Momi Medical Center, where he underwent X-rays and was released.

“It was a very traumatic, horrible experience,” Coffey said. “I was in shock, to be honest, because I never experienced anything like that before.”

“As stereotypical as it sounds, it seems like your life kind of flashes before your eyes. It’s the kind of stuff you see happening in a movie rather than in a plane, actually,” he added.

Lots of passengers were yelling and children were crying at the time of the sudden disruption.

The band members saw injured passengers with cuts, bruises and nosebleeds, and praised the flight crew.

“They were really good, so responsive and helpful,” Coffey said.

Overall, passengers were grateful to have landed safely and that none of the passengers and crew members were critically injured.

“We’re on the ground. We’re safe,” said Hurricane Fall band member Jesse Visser.

Air Canada arranged Honolulu hotel accommodations and meals for passengers.

The flight to Sydney is scheduled to depart Honolulu at noon today, according to airline spokeswoman Angela Mah.