Thursday, August 06, 2009

The Great Lakes Hurricane of 1996

I have lived in the Great Lakes region of the United States my entire life. I am a frequent visitor to three of the lakes and have seen all five. Bad weather is a fact of life sometimes on the Lakes and hurricane strength winds happen.

However, I would have never believed an actual hurricane had ever formed over the Great Lakes. But apparently, it happened. In 1996, the "Hurroncane" appeared in September.

Here is what the National Weather Service said about it:

The first likeness was its timing, forming over the Great Lakes right at the height of the typical hurricane season, September 11-15th, 1996. What started as a typical core-cold 500 MB low pressure system evolved into a warm-core system as it settled over the relatively warm waters of the Great Lakes, in particular, Lake Huron. The low pressure system actually had moved past Lake Huron but then retrograded, or was "drawn back", to the relatively warm waters of Lake Huron. (Similar to the tropics, the Great Lakes usually reach their warmest water temperatures late August into mid September.) The storm then deepened and intensified at the lower levels of the atmosphere compared to aloft, typical of a warm-core low. It is believed that the warm waters of Lake Huron and associated low level instability over the lake were, to a large extent, the major contributing factors in this storm's evolution. The storm went on to form a broad cyclonic circulation, including the "spiral bands and eye", typically seen in hurricanes! At one point, the cyclone produced tropical storm force winds (39 - 73 mph) and some of the spiral bands even had rainfall exceeding 10 cm (better than four inches), causing some flooding.

So I guess hurricanes are possible in the Great lakes and one may form again. I am sure if another one appears it will be pointed to as proof of global warming even though this has happened before. I hope my home is insured for hurricanes. I am not sure if our Great Lakes insurance policies include a clause for hurricanes.

2 comments:

Ed Darrell said...

It's not "proof" of global warming, but isn't it evidence of increased instability in the atmosphere, which is a predicted result of global warming?

1996 wasn't exactly the ice age. It's two years off of 1998, one of the warmest years ever, and a recent peak heat year.

In any case, it's a fascinating story. Thanks for posting it.

Anonymous said...

Both global warming and global cooling would lead to increased atmospheric instability. I wish NOAA would quit moving those dang thermometers!