A dozen North Jersey residents were treated for hand injuries Monday — one serious enough to require surgery — from trying to unclog snow blowers during the cleanup from the blizzard that dumped more than two feet of snow in some areas. At Hackensack University Medical Center, eight patients were treated for hand injuries, including a man who partially amputated two of his fingers, said Joseph Feldman, MD, chairman of the department of emergency medicine. The patient was headed for surgery, while the others were sutured in the emergency department and released, Feldman said. “I say to people, ‘Would you put your hand in a blender or under a lawn mower?’’’ Feldman said. “If the answer is no, why would you put her hand in a snow blower?'