Updraft: November 11, 2009 Archive

Would Today's Forecasts Save The Edmund Fitzgerald?

Posted at 8:45 AM on November 11, 2009 by Paul Huttner (1 Comments)

The routes of the Edmund Fitzgerald and the Aurther M. Anderson in November 1975.

I'll never forget the wind on November 10, 1975. I remember the howling winds in the Twin Cities whistling through the trees. When I heard TV news legend Dave Moore on WCCO-TV tell us that the Edmund Fitzgerald had gone down in Lake Superior, I felt the coldest chill of my life go down the back of my neck. Our family had recently circled Lake Superior on a vacation, and I remember thinking about the horror of being in that storm on that lake on a dark November night.

It was 34 years ago this week that the Fitz went down. Looking back, there were several weather scenarios that could have saved the Fitz. The Fitz could have stayed in port another 48 hours. They could have taken a shorter, more southerly route and possibly made Whitefish Bay before the height of the storm. If weather forecasters in 1975 had better data, they could have forecast the intense and rapid deepening of the storm system that would produce hurricane force winds and gigantic waves that sunk the Fitz.

Vastly improved data from weather radar and satellites and better numerical weather models have improved marine weather forecasts dramatically since 1975. In 1975 numerical models had just 3 "grid points" (data points) over Lake Superior. By 2000, that number had increased to 420. That's 140 times the number available in 1975.

The NWS office in Marquette Michigan has done excellent and comprehensive work on analyzing the "Fitzgerald" storm and others that have savaged the big lake in November.

The Fitz storm began as a fairly moderate low pressure system in Kansas on November 9th. The central pressure at the time was 29.53". By the morning of November 10th the surface low had raced all the way to Marquette, and deepened to 29.00". Later that evening, the low was near James Bay in Ontario with a surface pressure of 28.88". That's the equivalent of a Category 2 hurricane on the Saffir-Simpson hurricane intensity scale!

NOAA chart shows the intense surface pressure graident as the center of the surface low races north of Lake Superior.

That kind of rapid intensification was almost impossible to forecast back in 1975. The wave heights generated on Lake Superior were believed to be at least 16 to 18 feet druing the height of the storm. Since so called "peak waves" or rouge waves can superimpose on top of each other, it is believed the waves that sunk the Fitz may have been twice as high, possibly up to 36 feet or higher.

It appears that a combination of factors led to the sinking of the Fitz in November 1975. It's also quite likely that improvements in weather forecast would have saved the Fitz today. Those improvements are also a big reasons we haven't had any disasters like the Fitz in recent history.

Here are some great resources on the storm that sunk the Edmund Fitzgerald.

-NWS Marquette Michigan Edumund Fitzgerald Page
-Analysis of the November 10th 1975 storm
-Analysis of the November 10th 1998 storm
-Univeristy of Wisconsin Edmund Fitgerald data
-Surface loop of Fitzgerald storm
-UW Madison computer simulation of Fitz storm

PH

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Armistice Day Blizzard: Could it happen today?

Posted at 4:25 PM on November 11, 2009 by Paul Huttner

Abandoned cars buried on Excelsior Boulevard west of Minneapolis after the Armistice Day Blizzard. (Photo courtesy Minnesota Historical Society)

This is a bad weather week historically for Minnesota. Two of our fiercest and deadliest storms have occurred this week in November history. I blogged about The Edmund Fitzgerald Storm this morning which peaked on November 10th, 1975. The Armistice Day Storm of November 11, 1940 was one of the deadliest storms in Minnesota history.

The Armistice Day Storm is ranked #2 in the top 5 weather events of the 20th Century according to the Minnesota climate community. There are many unique aspects to the storm. One of the most commented on is the fact that the weather preceding the storm was unusually mild. Temperatures were in the 60s prior to the storm, luring duck hunters in shirt sleeves down to the Mississippi River that day.

Another facet of the storm was the rapid onset and temperature crash. Temperatures plunged 40 degrees on about 24 hours. About half of the 49 storm related deaths in Minnesota were duck hunters who drowned in or froze to death near the Mississippi River.

By the time the blizzard tapered off on the 12th, the Twin Cities had received 16.7 inches of snow, Collegeville 26.6 inches, and 20-foot drifts were reported near Willmar.

The powerful Armistice Day surface low winds up near Des Moines.
(Credit: NOAA)

The Armistice Day blizzard was not well forecast. In fact, the U.S. Weather Bureau office in Chicago that had forecast responsibility was unstaffed overnight during the storm. There were no updates on the storms increasing severity as it strengthened that night. That prompted local officials to pressure the Weather Bureau to add forecasters to the Twin Cities weather office. It was The Armistice Day Storm that was the likely catalyst to creating what is now the Twin Cities NWS office.

Another interesting part of the storm is what occurred over the Tacoma Narrows Bridge in Puget Sound as the storm passed. High winds caused the famous "Galloping Gertie" bridge collapse.

There is a good meteorological reason why some of our most intense storms occur in November. Temperature differences are among the greatest between Canada and the central U.S. in November. Single digit arctic air can pool to the north, and crash into relatively milder air that lingers in the 60s and 70s in the central U.S. Minnesota lies in the battle zone in between these two air masses.

The Armistice Day Storm would surely have been much better forecast today than in 1940. The Halloween Mega-Storm is a good example of a a forecast success story in modern times. Though eventual snow amounts were under forecast, the public was prepared for the storm well in advance. That saved lives during the biggest snowstorm in Twin Cities' history.

PH