For the carefree nomads who call themselves “Deadheads,” it was near-nirvana - a night of dancing and partying as an early summer rain fell.

But the celebration took a tragic turn just before midnight Wednesday when a wooden deck collapsed at a campground lodge, injuring more than 100 Grateful Dead fans camping near this eastern Missouri town.

Most of the victims were in their teens and early 20s. Sixteen were admitted to hospitals; five were in critical condition Thursday, including Dustin Grella, 24, of McDina, Ohio, whose neck was broken.

Most of the others suffered broken bones, said Martin Limbert of the St. Charles County Ambulance District.

Police said heavy rain sent hundreds of people scurrying to cover on or under the deck attached to the lodge at the Pinewoods Park campground, about 40 miles west of St. Louis.

The 40-foot-by-10-foot deck was about 12 feet off the ground and was covered by an overhanging roof. The roof also collapsed.

St. Charles County investigators are trying to determine the cause of the collapse. Some party-goers blamed it on the weight of hundreds of people.

“I was underneath,” said Mike Luden, 20, of St. Louis. “Everybody was just partying. Then there were two loud snaps, and the whole thing just came down on top of everybody.”

About 4,000 “Deadheads” have taken up residence at the campground. Many fans follow the band on its tours around the country. The Grateful Dead performed Wednesday and the band was scheduled to play again Thursday in suburban St. Louis.

“It amounts to a tragic accident happening to members of your family,” said Dennis McNally, publicist for the band. “In our hearts, we’ll play tonight’s show for them.”