NOAA’s Office of Coast Survey just released major updates to the official navigational charts of the Yukon River—a vital waterway serving many interior communities of Alaska. The Yukon is frozen more than half the year, limiting the window for barges to deliver the fuel, building materials, heavy equipment, and other supplies that cannot be transported by air. NOAA has developed a new process for updating the Yukon charts with the most current shoreline information, which is expected to improve safety and efficiency of navigation on the river and make delivery of vital supplies more reliable.
Like other major rivers in Alaska, ice and strong runoff currents shift the Yukon’s shoreline and natural navigation channel every year. Vessels on the river must find the best track in and out of the numerous communities they serve and often find the channels and shallows have shifted since the year before. While their vessels are built to “go dry,” each unintentional grounding causes delays, lost time to complete a season’s work before the weather turns, and necessitates reporting to the U.S. Coast Guard. While the risk of a grounding is a normal outcome for some voyages, each new contingent assigned to Alaska must discover these Alaska norms.
Tug companies that operate on Alaskan rivers, particularly Vitus Energy, have been working with NOAA to develop solutions for these complex rivers. Past attempts have not solved the cartographic problems rooted in changeability or proved reliable to support navigation.
This year, NOAA’s National Geodetic Survey’s (NGS) Remote Sensing Division and the Office of Coast Survey developed a more reliable solution that emphasizes timeliness and automation. Due to the scarcity of contemporary satellite imagery that is not obscured by cloud cover, or taken at high river stages, some trade-offs were evaluated. It was determined that the shoreline would be represented even if some sections may be covered by water at the lowest river stage (typically, shoreline is represented at higher water levels such as “drying heights.”) Shoal areas extracted from the imagery isolated and separate from the sloping shoreline would be represented as blue-tinted obstruction areas on the Electronic Navigational Charts (ENCs). The most recent updates from NOAA’s Office of Coast Survey shift the operating paradigm toward a higher level of safety and predictability.
This month, the Remote Sensing Division fast-tracked an automated shoreline extraction from satellite imagery captured between October 24, 2024 and May 26, 2025. The resulting update reflects the dramatic changes in the shoreline and visible shoals (areas where the water is particularly shallow and unsafe to navigate through). Coast Survey cartographers then began building and immediately using the automated shoreline to rapidly ingest and update these changes into the ENCs. This initial effort included work preparing the ENCs and workflows for a largely automated update process in the future.
National Geodetic Survey and Coast Survey’s cartographers will repeat this process annually, ensuring updated shoreline data and ENCs are released every year before the shipping season commences.
See some before and after examples using the sliders below:
Along the Yukon River, near Sunshine Bay
Near the mouth of the Yukon River
Coast Survey is always looking for feedback on our products and their usefulness to the communities that use them. Please contact your regional navigation manager, or use our ASSIST tool to provide feedback.