What is overflow? Any experienced snowmobiler can answer that question. Overflow, as the term is used in Alaska, is water flowing on top of the ice. No Alaska winter excursion would be complete without it. Overflow can occur at any temperature. Sometimes it is visible, most times it is not. Either way it can provide an adventure. As I always contend, an adventure is just another way of saying you made a mistake. Snowmobilers who drive big mountain sleds with tons of horsepower and paddle tracks scoff at visible water on the ice. They grab some throttle and go for it.