In the early morning hours of May 31, 1998, I was living in northern Ohio and watching one of the most ominous weather systems to hit the United States sweep rapidly across Minnesota, Wisconsin, Lake Michigan and close in on my parents’ house in western Michigan (they didn’t have cable or a computer, so I was their weather warning system). The storm was a Derecho:

The derecho (pronounced Deh-RAY-cho) is a violent, widespread windstorm emanating from long-lived thunderstorm complexes. Derechos produce damaging, straight-line winds of about 60 to 100 mph that are strong enough to down trees and power lines. They rush across a region along paths tens of miles wide and hundreds of miles long. Derecho damage is continuous over a large area.

Gustavus Hinrichs coined the term in the 1880s when he served as Director of the Iowa Weather Service. Derechos are straight-line winds in contrast to the circular winds of tornadoes. For this reason, Hinrichs named them from a Spanish word meaning “straight ahead” as a contrast to “tornado,” which derives from the Spanish for “turning.”

To be classified as a derecho, the storm must produce winds in excess of 58 mph over a path at least 450 km (280 miles) long. When a derecho strikes, its damaging winds, often gusting to 155 mph, may blow for several hours. Thus, the dangers associated with derechos arise from both the strength and duration of the wind. Derecho widths vary from 50-300 miles, thus, they are also large spatial events, rivaling the area covered by a hurricane. (source)

As the storm formed the classic bow shape as it approached Michigan, the line was moving 70 mph with winds approaching 130 mph. Nearly one million people in the state of Michigan were without power following this storm – some as long as 10 days. Because I was in Ohio (it moved just north of me), I was watching this storm on my computer and was able to contact my mom and get them to their basement. I stayed on the phone with my mom until the service went out. I could hear the roar as this monster approached their house. Fortunately, a neighbor checked on them and let my mom use their cell phone so she could call me and tell me they were ok. They had trees down and were without power for several days, but they were fotunate compared to the damage and loss of life experienced by others across the state of Michigan. Ultimately, the storm traveled almost 1000 miles from Minnesota to New York in about 15 hours.

Following is the radar of this storm as it started in Minnesota and roared through Michigan. It is still one of the most impressive radar loops I have ever seen. Following the radar loop are some links to pictures and accounts of the storm.

Derecho Event – May 31, 1998

Storm Prediction Center – NOAA

Wood-TV8 (take time to watch the video on this page … it is a report about the Derecho event by our favorite Meteorologist, Bill Steffen. He reports some historical information from this event that is incredible).

This storm is still considered to be one of the most powerful non-hurricane events to ever strike the United States. Hopefully we won’t see another one any time soon.

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