When Wisconsin was Slammed by Category 3 Hurricane-Force Winds

It rarely happens, but every now and then the winds in Wisconsin get fierce which is exactly happened on a 4th of July many many years ago. It was on that day that parts of Wisconsin were slammed by the equivalent of category 3 hurricane-force winds.

This quest began as a curiosity about what the highest wind speed ever recorded in Wisconsin. My interest was about non-tornadic winds and what I've learned comes directly from the National Weather Service. They tell the story of what happened during the morning of a 4th of July decades ago.

The event is called the Phillips Wisconsin Independence Day Derecho of 1977. The derecho formed in western Minnesota and began a 12-hour trek across Wisconsin and even Michigan. The National Weather Service described the peak of the event:

"At its peak, the winds were estimated to be 115 mph across portions of north central Wisconsin"

According to the Saffir-Simpson scale, those winds that impacted Wisconsin that 4th of July were of category 3 hurricane strength which can and does cause major devastation.

Let's be clear that what moved through Wisconsin that July 4th in 1977 was not a hurricane as that would mean sustained winds and not the straight-line variety that were a part of that historic derecho. However, the damage the storm caused was beyond belief. The NWS says the path was "10 to 20 miles wide and was over 160 miles long" and 850,000 acres of trees were either damaged or destroyed.

The overall cost of the July 4, 1977 Wisconsin derecho was $24 million dollars which would equal more than $125 million in 2024. Let's hope that the state never experiences straight-line winds of that magnitude ever again.