Weather experts have "hindcasted" the storm that sunk the Edmund Fitzgerald on Lake Superior in November 1975.
Hurricane-force gusts and waves coming from an unexpected angle likely contributed to the disaster immortalized by Gordon Lightfoot in the song "The Wreck of the Edmund Fitzgerald," researchers say.
All 29 crew members died.
"During the late afternoon and early evening of Nov. 10, conditions deteriorated rapidly with winds in excess of 69 mph, hurricane-force gusts [over 74 mph] and waves more than 25 feet high," said Thomas Hultquist, science and operations officer at the NOAA National Weather Service forecast office in Negaunee, Mich.
The freighter, thought like the Titanic to be invincible, was heading south. Waves were traveling west to east, the new analysis shows. This could have created a hazardous rolling motion. The ship sank about 15 miles (24 kilometers) from Whitefish Bay.
Lake Superior is the largest of the Great Lakes.
"While high winds on Lake Superior are not rare, it is unusual for the waves to get that high on the lake," said one of Hultquist's co-authors, David Schwab of NOAA's Great Lakes Environmental Research Laboratory in Ann Arbor, Mich. "It's unlikely that Captain Ernest McSorley, the skipper of the Edmund Fitzgerald, had ever seen anything like that in his career."
The findings are detailed in the May issue of the Bulletin of the American Meteorological Society.