A Bit of Derecho History

It’s always interesting when you learn about something that suddenly pops up again. Last summer, while traveling through Minnesota, I visited the Forest History Center, where I learned about something called a “blowdown.” It was explained that a blowdown is a derecho that hits a heavily forested area, because it blows down all the trees. This led to my looking up derecho, which comes from the Spanish for “straight,” because it is a high wind that blows straight, rather than swirling, as with a tornado.

The display at the Forest History Center showed stunning photos from a blowdown that hit northern Minnesota, moved across the Boundary Waters and swept into Canada in 1999. This one storm flattened nearly 500,000 acres of trees. The display noted that this area was greater than the area destroyed by the eruption of Mount St. Helens.

That storm, however, was far from alone. There was a blowdown in the Adirondacks in 1995, when a derecho leveled 150,000 acres of forest, but the so-called Big Blowdown in the Adirondacks was in 1950, when a derecho flattened 800,000 acres of timber.

So when the term “derecho” popped up on the news, I was ready to be horrified. What surprised me, as I looked into it more, is that I hadn’t heard more about this phenomenon before, because these storms have occurred with some frequency in the U.S. I wondered if it was because they were so often in less populated areas, or whether it might be because they were generally a surprise, rather than offering the long, dramatic build-up we usually see for a hurricane.

The storm was first described and given its name in 1877 by Dr. Gustavus Detlef Hinricks, a professor at the University of Iowa and founder of Iowa’s first weather service, following the appearance of this type of storm in Iowa in that year.

The thing that strikes me is how resilient both forests and humans are. Because all the blown-down forests have grown back and cities and towns have been rebuilt, and hence we are surprised by the new destruction, because both nature and humans have forgotten. And yet I have also been reminded of that resilience, as videos start to pop up with efforts well under way to rebuild after this most recent storm.

Praying that all those affected by this most recent derecho recover quickly. Simply knowing that a phenomenon is natural and even relatively common does not make it any less horrifying.

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