After Halloween, beware of the ‘Witches of November’ storm systems

If the vivid fall color hasn’t reminded you how close we are to November, perhaps the strong winds from this past weekend did.

As we move toward Halloween, meteorologists really do start looking for “witches.” Of course, we are not talking about the greenish-colored lady dressed in all black flying on a broom. Instead, this witch is the name of a storm system that creates strong winds that frequently blow across our region in late autumn.

Typically, strong winds that occur this time of year are caused by intense low atmospheric pressure over the Great Lakes. When cold, dry air starts to surge southward from Canada, it then converges with warm, moist air moving northward from the Gulf of Mexico.

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This is the initial spark that gets a storm system started. A strong jet stream which is normally found above the northern U.S. in late October into November helps intensify these systems further and steers them above the Great Lakes.

These storm systems are often referred to, at least in history, as the November Witches of the Great Lakes. These powerful storms have also been called November Gales, White Hurricanes, and Freshwater Furies. Whatever you call them, these storm systems are fueled by the massive, relatively warm Great Lakes.

Sometimes, these storm systems can explode, intensifying as strong as category 1 or 2 hurricanes.

Once this storm system moves above the lakes, the relatively warm water adds the final ingredient to an explosive mixture, and a Great Lakes hurricane is born. They can produce wind gusts greater than 100 mph, drop several inches of rain and snow, and produce record low barometric pressure readings.

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These storms happen with enough regularity that they are known as a bane for the people living along the Great Lakes, and a foe for the ships that cross them. Since the mid-1800s, there have been more than two dozen of these cyclones recorded over the Great Lakes, most of them in November.

The worst storm on record was known as The Big Storm of 1913, and it affected all five Great Lakes. Thirteen ships sank, and more than 240 men lost their lives, most of them on Lake Huron. Winds were estimated at 90 mph, with waves of more than 35 feet, along with whiteout snow squalls.

However, the most infamous storm was dubbed the Witch of November – striking on Nov. 10, 1975. This storm produced winds of 100 mph, creating 35-foot waves on many of the Great Lakes. This storm sunk one of the largest cargo ships of the time, the Edmund Fitzgerald, killing all 29 crew members.

If you have lived along or near the Great Lakes long enough, then you know that this time of year we are entering can bring about some intense storm systems. This past weekend is just a small reminder of the intense winds that can hit our region this time of year. It is all a part of the changing of the seasons.

The last major Great Lakes storm struck on Halloween of 2014, forming above Lake Michigan. One might say we may be due for another major autumn storm, luckily, improvements in building codes and technology has meant impacts of such storms are less than they were many years ago.

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