In an organized fashion, groups of brave swimmers jumped one after another into the 50-degree waters of Lake Lanier late Thursday morning. The 18th annual Polar Bear Plunge at the Olympic venue offered mild weather above ground, but swimmers wasted little time getting out of the water and getting wrapped up in a towel. Following the plunge, swimmers could warm up with a bowl of chili or hot chocolate inside the Lanier Canoe and Kayak Club.