Winter Weather Creates Chaos on Ice

And this cold, winter weather means frozen lakes and the danger of falling through thin ice. Abc's bob woodruff on how to survive if you become trapped in icy water. Reporter: It is a familiar winter... See More

And this cold, winter weather means frozen lakes and the danger of falling through thin ice. Abc's bob woodruff on how to survive if you become trapped in icy water. Reporter: It is a familiar winter picture. Dozens of youtube videos show kids and young daredevils, having fun venturing out on the ice. But here's what can happen in an instant. Just in the past two weeks, two teens trapped four hours, clinging to a tree. Falling into frozen waters, sends your body into cold shock. This doctor demonstrates. You start gasping and hyperventilating. Reporter: He says get your breathing under control, fast. It's a race against hypothermia. You're losing heat. Your core temperature dropping. If you're able to thread water, you have as little as 15 minutes before losing consciousness. So frigid, rescuers don full-body thermal suits like the one I wore in norway as a precaution. Don't flail your arms like this. Always keep them above the water so they don't freeze. Your arms are key. And don't remove your clothing, including your boots. It will actually help you to stay afloat. Out on thin ice, every move can make the difference between life and death. For "good morning america," bob woodruff, abc news, new york.