WINNIPEG, Manitoba - A group of schoolchildren fell down from a 5m or so high structure during a field trip on Wednesday, in the western Canadian city of Winnipeg, but avoided serious injuries in an incident that officials said could have been much worse.

Children from Winnipeg’s St John’s-Ravenscourt School were visiting the historic Fort Gibraltar when the fall happened, sending 16 children and an adult to hospital.

The children were 10 to 11 years old and suffered non-life threatening injuries, said Dr Karen Gripp, of the Winnipeg Children’s Hospital, in a televised briefing.

One patient was being kept in hospital for observation, while the rest either had been or will be discharged today, Dr Gripp said.

“It could have been so, so much worse,” she said.

“Fortunately, or serendipitously, it was not very busy, and we were all caught up at the time, so we had empty rooms, we had nursing staff available.”

Winnipeg Fire Paramedic Service official Michelle Bessas said at the briefing the children fell from a structure at Whittier Park, where the fort is located, but the reason for the fall was not yet clear.

The structure was approximately 5m tall, she said, adding that paramedics assessed 28 patients, 17 of whom were taken to hospital.

“Our thoughts go out to all the students, teachers, and families of St John’s-Ravenscourt affected by today’s terrible accident at Fort Gibraltar,” Manitoba Premier Heather Stefanson said on Twitter.

Fort Gibraltar, in the province of Manitoba, is one of over 1,000 protected national historic sites in Canada. REUTERS