A tsunami warning triggered by a powerful 8.8-magnitude earthquake off the Russian coast Tuesday forced cruise ships to leave Hawaiian ports, including Norwegian Cruise Line‘s Pride of America, the only large, US-flagged and US-crewed cruise ship in service.

While the evacuation was largely precautionary, some passengers on an excursion were left behind in Hilo, Hawaii, as the ship sailed away without them.

Tiffany Oliver and her 18-year-old daughter were among a group of guests from Pride of America on a day trip to Hawaii Volcanoes National Park when emergency alerts were issued, according to the New York Times. 

At 2:46 p.m., while en route to the park, passengers received an alert from the National Weather Service warning of an incoming tsunami and instructing recipients to move to higher ground.

Despite the warning, the excursion bus continued to the park, where visitors were told to enjoy the site, but were urged to return to the ship by park officials a few minutes later.

The bus began the 45-minute drive back to the Port of Hilo as passengers attempted to reach Norwegian Cruise Line customer service, asking that the ship be held. Initially, they were told the vessel would wait for them.

However, at 3:38 p.m., while the bus was still roughly 20 minutes away, Norwegian informed the group that the Pride of America had to depart due to a request from the state’s Department of Transportation.

“In response to local emergency procedures and to prioritise the safety of our guests and crew, Pride of America was required to depart Hilo, Hawaii, immediately,” Norwegian Cruise Line said in a statement, adding that the ship left at 4 p.m., two hours ahead of schedule.

When the group arrived at 3:55 p.m., they could still see the ship at the dock, but the gangway had been raised and mooring lines were being let go.

Several of the affected guests shared their experiences on social media. Images show them later sheltering in the Waiākea High School gymnasium, where they spent the night on the floor or inside tour buses.

By Wednesday morning, local authorities cancelled the tsunami advisory and issued an all-clear. Norwegian confirmed that Pride of America remained at sea awaiting permission to return to port and retrieve the stranded passengers. The total number of guests affected has not been confirmed.

Pride of America is the only large, ocean-going cruise ship registered in the United States and crewed predominantly by Americans, due to the requirements of the Jones Act and Passenger Vessel Services Act, which prohibits foreign-flagged vessels from operating between US ports.

The global cruise fleet is predominantly US-owned by Carnival Corporation, Royal Caribbean Cruises Group, and Norwegian Cruise Line Holdings, but operate under flags of convenience such as Liberia, the Bahamas, Panama, and Malta.