A snowmobile with two riders on board fell through the ice on the bay of Green Bay on Christmas morning.Fire officials in the Village of Suamico, where the incident occurred, said the riders had safely "self-rescued." However, the snowmobile is sunk in about 12 feet of water.Suamico fire chief Joe Bertler said the snowmobile was about 200 yards off the shoreline when it went through the ice. A resident on Cottage Row called 911 to report the incident.Bertler said residents are strongly encouraged to notify authorities if they self-rescue and leave the scene. He said, in this case, multiple rescue teams were deployed, not knowing if the riders were in the water.