The Okhotsk Sea coast of Hokkaido is rushed by dtift ice. Sometimes aquaculture facilities and fishery resources have been damaged by the movement of drift ice. And they affect activities of port and harbor. It is required that ice control facility are constructed for decreasing their damages.
When we design the Ice control structure the data about drift ice (size, thickness and concentration ratio) is needed. The authors observed drift ices at the Coast of Okhotsk Sea and clarified the distribution of ice size and the relation between size and thickness.