NORTHFIELD - A 51-year-old Canterbury woman was seriously injured in an All-Terrain Vehicle rollover Monday night.

The accident happened about 6:40 p.m. Liane Hoyt of Canterbury was operating an ATV on a snowmobile trail in Northfield when the machine rolled over on top of her, causing serious injuries. Hoyt was riding with a group, but none of the other riders saw the accident.

When companions got the machine off her, Hoyt, who was not wearing a helmet, was unconscious. They called 911 for assistance.

Tilton/Northfield Fire and Rescue personnel responded to the scene with an ambulance, along with Northfield police and a New Hampshire Fish and Game officer.

Hoyt was transported to Concord Hospital, then airlifted by DHART to the Dartmouth Hitchcock Medical Center in Lebanon.

"This serious incident underscores the importance of wearing a helmet when operating an ATV or snow machine," said Fish and Game Conservation Officer Brad Morse.

The incident remains under investigation by the New Hampshire Fish and Game Department.

ptracy@unionleader.com