The bitter cold at Niagara Falls is part of a polar vortex onslaught of frigid air that's plagued the central and eastern U.S ...

From nearly invisible black ice to freezing rain and sleet, here's how common winter weather hazards form, why they're so dangerous.

If you wonder how cold is too cold for your dog out for a walk or outside time, it can depend on the breed, size and coat your dog has.