http://www.chicagotribune.com/news/nati ... ?track=rss
Why the Edmund Fitzgerald sank
Storied ship victim of fluke of nature
By James Janega
Tribune staff reporter
May 21, 2006
Fighting the worst seas of his life, the captain of the Edmund Fitzgerald aimed the wallowing iron freighter for the safety of Lake Superior's Whitefish Bay. Just 17 miles away, the bay seemed to offer the best hope of saving the ship and 29 crewmen.
What Ernest McSorley could not know is that he was steering his ship straight for a dangerous fluke of nature, according to weather scientists who have used modern computer models to analyze the 1975 storm that produced one of the Great Lakes' most famous wrecks.
The winds that evening were so strong--50 m.p.h., with gusts up to 70 m.p.h.--that they are seen only once or twice in a decade on Superior, weather scientists found. Worse, the winds blew from a direction that sent them unobstructed over 180 miles of open lake, pushing waves the size of apartment blocks right in the ship's path.
The models show the worst of the weather was confined to a small corner of the lake and lasted only a few hours. Into that brief, destructive window sailed the Fitzgerald. Only 10 miles behind sailed the freighter Arthur Anderson, which survived.
"With the models, we just saw this bull's-eye with the highest waves coincident with where the Fitzgerald was," said Thomas Hultquist, the science and operations officer for the National Weather Service office in Marquette, Mich. "They really couldn't have been in a worse place at a worse time."
Hultquist is the lead author of a paper, published this month in the Bulletin of the American Meteorological Society, that offers the fullest picture to date of the Nov. 10 storm that sank the Fitzgerald, immortalized in the 1976 ballad by Gordon Lightfoot.
The article tracks the ship's eastward course across southern Lake Superior for two days as the storm built from a blustery low-pressure disturbance in Kansas to a gale off the Upper Peninsula of Michigan.
Until now, reports of the weather had been anecdotal.
"It was one of the biggest and wildest seas I have ever been in, I mean fast," Cedric Woodard, pilot of the Swedish vessel Avafors, told Coast Guard investigators. "The sea was straight up and down, and a lot of [waves] were coming at you. It was not like big rollers."
To find out what made the storm so deadly, Hultquist and meteorologist Michael Dutter of the National Oceanic and Atmospheric Administration in 2002 began feeding known weather data into atmospheric models.
Only 31 observations were available on Lake Superior from Nov. 9-10, 1975, amounting to a glimpse every hour and a half at an area the size of South Carolina. After models expanded on that information, NOAA oceanographer and third co-author David Schwab used the predicted wind fields to create wave models.
"When I ran the simulations of the waves and then examined the wave heights hour by hour, there was a moment where you realized, Oh my gosh, at this hour, here's where the Fitzgerald sank," Schwab said.
Named after the president of Northwestern Mutual, the Edmund Fitzgerald launched from Detroit in 1958. A two-block walk from the forward pilothouse to the stern rail, it displaced 13,632 tons empty and was the biggest ship on the Great Lakes until 1971. Thirty-one years later, it's still the largest of more than 1,000 ships to be lost on the Great Lakes.
At the time it began its last trip--from Superior, Wis., east across the lake toward Detroit--McSorley knew barometric pressure was falling rapidly and that winds would shift counterclockwise to again come from the west. Gale warnings were issued shortly after the Fitzgerald departed, and later warnings predicted even worse.
Similar conditions happen every 6 to 10 years, the researchers found, and that weather in itself wouldn't have stopped the freighter from sailing.
On Nov. 9 the Fitzgerald began by heading into a gentle north wind with waves a few feet high. By dawn the next day, the lake was rolling as the wind shifted around from the east, and by 10 a.m. Nov. 10 the ship found itself bobbing in the calm center of a massive low-pressure trough.
But the wind grew heavier as it swung around from the west, and like a snowplow it forced ever-higher waves across the lake.
North of Whitefish Point, the waves went from almost nothing to 30 feet high and higher in just six hours, fed by whistling gusts and swirling with snow flurries. Six hours later, they fell to half that size--survivable--but it was too late for the Fitzgerald, which was last heard from just after 7 p.m.
The wreck was so sudden there wasn't time for a distress call, and the mystery of how the ship sank has never been settled. A Coast Guard inquiry suggested the loaded ship had been riding low in the water, may have struck a shoal near Caribou Island, and had loose hatch covers that admitted crashing water from the storm.
The final report concluded the ship may have nose-dived into a large wave, its 26,000-ton cargo of iron ore clattering forward and pulling it in seconds to the lake floor 535 feet below.
"The main lesson to learn from it from a forecaster's perspective is to understand how severe conditions can be and how quickly they can become that way," said Hultquist. "If a storm of that magnitude were forecast now, these ships would be in port. They wouldn't be out there as these storms are upgrading."
Ship masters already have taken the lesson to heart, said Sean Ley, development officer of the Great Lakes Shipwreck Historical Society.
"The larger the ship, the more chance of safety you've got, but the ship still can be damaged and there's a chance for catastrophe," he said. "They don't want to be the Edmund Fitzgerald."
----------
jjanega@tribune.com 
