APPLETON — A Rockport woman was killed when the snowmobile she was driving collided with one driven by her son.

Jan M. Richardson, 43, was visting friends in Appleton Saturday when the crash occurred. She and her son Josh were riding snowmobiles in a field at 11:30 p.m. when they collided, said Cpl. John MacDonald, of the Maine Warden Service.

The woman was reportedly not wearing a helmet, he said. Union rescue responded and tried unsuccessfully to resuscitate her and she was pronounced dead at the scene, MacDonald said.

Her son was taken to Waldo County Hospital with injuries that were not life-threatening.

The crash is under investigation but speed and alcohol appear to be factors in the crash, MacDonald said.

Correction: This story was revised at 2:35 p.m., March 6, 2012, to state that Jan M. Richardson’s snowmobile collided with one operated by her son Josh.