HALLOWELL — Officials are investigating why the roof of the Kennebec Ice Arena collapsed Wednesday afternoon during a brief break between a public skate and youth hockey.

Nobody was injured in the collapse, which occurred while only three people were inside.

Jeff Thompson, a volunteer for Maine Amateur Hockey who was on the second floor of the arena when it collapsed, said the first thing he saw was snow falling onto the ice below.

“The first part, there was a section that came down, and then the rest came down like a big sheet,” he said.

Thompson ran from the arena’s north end, where the collapse was the worst, to the south corner. He and two other men, rink manager K.C. Johnson and a skate shop employee, made their way outside.

State and local emergency responders converged on the building after the collapse.

People who gathered to see the crumpled building marveled that nobody had been hurt and reflected on what was lost and the countless memories that had collected in the arena.

“It’s tragic,” said Dan Gagnon. “My kids grew up in this building.”

Gagnon said he has played in a men’s hockey league at the arena for about 20 years. He was scheduled to play Wednesday night. “Thank God it happened when it did,” he said.

The collapse, reported around 3 p.m., left little hope of repairing the building. The length of the 240-foot-long building’s roof collapsed, folding in the upper metal walls. Most of the dozen structural steel girders that spanned from the ground to the roof were bent; one had been ripped from its concrete mooring.

Ceiling tiles and insulation littered the parking lot, blown from the building by wind generated by the collapsing roof. One large chunk of insulation rested in trees 30 feet above the ground.

The arena, which opened in 1970, was home to high school and club hockey teams and offered public skating. The building had recently been remodeled, including a renovation of the locker rooms. The updates included old boards and glass from the Fleet Center, home of the Boston Bruins.

“Quite a few improvements were made,” Gagnon said. “It was really shaping up well.”