SHIRLEY, Mass. (AP) — A large ice chunk fell from the sky and hit a house in Massachusetts, damaging the roof of the home, the homeowner said.

Jeff Ilg said he and his wife, Amelia Rainville, suspect the ice fell off an airplane traveling to Boston Logan International Airport. Neither the couple nor their two children were hurt when the ice chunk, which Ilg said was initially estimated to be 15 to 20 pounds (six to nine kilograms), hit the roof on Sunday night.

“We heard an explosion, basically,” he said on Thursday. “The loudest pop, bang I’ve ever heard.” Then they heard debris rolling down the roof onto a lower roof, he said. Initially it was thought the house was struck by lightning.

The Federal Aviation Administration said it’s investigating.

The couple ran upstairs to check on their children, who were sound asleep despite the noise. They then ran around the house to see what happened and then outside where Ilg said he saw a giant partial block of ice on the back step, and debris scattered around the backyard and on the roof.

“I had no idea what this was,” he said. He grabbed a flashlight and started looking for damage but couldn’t see any at first. His wife called police and then he spotted hole in the roof. He ran up to the attic to see if there was a hole.

“Sure enough it was in there and it was big,” Ilg said. The impact on the outside was about 18 inches to two feet (45 to 60 centimeters) in diameter, he said, but the damage to the inside was bigger.

Ilg and his wife collected 10 pounds (four kilograms) of ice in bags but there was plenty more to collect, he said.