Out-of-service buoy and winter storms raise concerns

An out-of-service buoy and a series of recent storms have combined to raise concern at the Council about tanker transit procedures during period with the high wind speeds and wave heights in which tankers are allowed to travel through Prince William Sound.

Seal Rocks buoy out of service


From May until December of 2018, a critical buoy located near Hinchinbrook Entrance was out-of-service. This buoy, referred to as “Seal Rocks buoy,” collects wind speed and wave height data. That information is used by the U.S. Coast Guard to make decisions as to whether Hinchinbrook Entrance is open or closed to outbound laden oil tanker traffic. When this buoy is inoperable, the U.S. Coast Guard uses data from two nearby buoys, Cape Cleare and Cape Suckling, along with reports from Edison Chouest Offshore, or ECO, tug crews that are sent out to observe wind and waves to make Hinchinbrook Entrance open and closure decisions.

In November and December, several winter storms came through Prince William Sound that raised concern about these alternate methods for reporting weather conditions at the Entrance.

Problems arise during November and December’s stormy weather

On the afternoon of November 12, an outbound laden tanker departed its berth at 1:30 p.m., after an ECO utility tug noted wind and wave heights were below closure conditions at noon. At 1:37 p.m., however, the same ECO tug reported 50 knot winds with higher gusts. The Coast Guard closed Hinchinbrook Entrance a few minutes later. The tanker continued its outbound transit for six hours all while Hinchinbrook Entrance remained closed. The tanker then made the decision to conduct racetrack circles to maintain a holding pattern in Southern Prince William Sound until 9:30 p.m., when Hinchinbrook re-opened.

The ECO utility tug had left an oil spill response barge moored in Port Etches while it was away observing weather at the Entrance. At around 11 p.m., high winds caused the barge to break loose from its mooring, resulting in the barge running aground. There were no injuries and the barge sustained only minor damage. In addition, at some point the ECO utility tug lost one of its anchors, and a thruster failed. Alyeska is still investigating these occurrences.

Two other storms, one in late November and another in December, re-emphasized the concerns. During these two storms, ECO tugs reported wave heights just below closure as laden oil tankers departed through Hinchinbrook Entrance. In both cases, weather data from Cape Cleare which is approximately 60 miles southwest of Seal Rocks, and Cape Suckling, approximately 125 miles to the southeast, indicated that wave heights were significantly above closure limits, and forecasts predicted weather to worsen.

Further evaluation needed

In a February letter to the Coast Guard, the Alaska Department of Environmental Conservation, and the industry, the Council recommended improvements be made to clarify the procedures for reporting weather conditions when the Seal Rocks buoy is inoperable. In addition, the Council recommends further evaluation of the buoys, their locations, and consideration of additional buoys to improve the weather reporting in the area.

“The Council’s main concern is if a tanker experiences a problem during one of these storms, the tugs and crews will be called in to assist. We are concerned about the safety of the tugs and crews, and their ability to prevent an oil spill in weather conditions that are near or above established Hinchinbrook closure conditions,” said Donna Schantz, Executive Director for the Council. “We’ve also conducted studies that show how an effective oil spill response is not possible in the higher sea states, especially during the winter months.”

Read more:

The Council’s full recommendations:

The Council’s 2007 report on the “response gap” in Prince William Sound: