The first winter navigation in the northwestern part of the sea of Okhotsk: ice navigation conditions

The severity of the ice conditions and absence of winter maritime operations in the area in the winter season 2024/25 explain the limited understanding of ice navigation conditions in the northwestern and western parts of the Sea of Okhotsk. In 2024, the Port Elga coal terminal was built and the year-round transportation of coal started from the Elga deposit to Cape Manorsky and then to the southern Sea of Okhotsk. In this study we conducted continuous monitoring of the first winter navigation season in the northwestern Sea of Okhotsk. Based on the results, we identified several specific features of the ice navigation conditions. Specifically, ice conditions in certain localized areas became more severe due to dynamic factors and changes in the ice structure during the spring melting period. In the course of the study, we obtained and analyzed information on the characteristics of navigation in an area where there had been no previous permanent winter navigation and determined the position of optimal navigation routes in the northwestern and western regions of the Sea of Okhotsk at various stages of ice formation. The 2024/25 winter-spring navigation was analyzed over several key periods, as ice conditions became more difficult. At the beginning of the season, navigation followed the shortest southern route and was easy for ships with ice class Arc4 or higher. The second period required icebreaker assistance. In the third period, navigation routes shifted northward due to more difficult ice conditions. In the fourth period, icebreaker assistance was provided by two icebreakers simultaneously. In the fifth, most challenging period, ship traffic was almost stopped due to severe ice conditions. The main conclusion of the study is the need for both continuous monitoring of ice conditions and specialized shipboard ice observations to provide timely forecasting of ice conditions, thereby improving the quality of specialized hydrometeorological support for ships during maritime operations.

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