SEARSPORT — Ice on Half Moon Pond proved too thin for a father and his minor son walking on it  Dec. 28, and they fell through. Both made it out of the water safely.

A camp owner who witnessed the incident called 911 just before 2 p.m., according to Town Manager James Gillway. It was first reported that they were on an ATV, but when first responders arrived at the scene, they determined there was no ATV involved.

It is unclear why the two were walking across the ice, but when they went through they were able struggle back to shore, Gillway said. When the first responders from Searsport Ambulance Service arrived, the two were warming up in their vehicle and refused medical treatment.

The town does not usually get these sorts of calls but the ice is not yet safe for people to be on, Gillway said. This was the first call in town this season involving people falling through the ice. “No ice is safe at this point,” he said. “… It’s not a safe year yet.”

Maine Department of Inland Fisheries and Wildlife urges people to stay off of light gray to dark-colored ice, according to its website. This type of ice has weak density and cannot hold weight. People should also stay off white to opaque ice and mottled and slushy ice, which is referred to as rotten ice.

Blue to clear ice has high density and is strong, according to the IFW website. It is the safest ice, if thick enough. People should stay off the ice if there is less than 4 inches of ice over a body of water. More information regarding ice safety can be found on the IFW website.