Derecho Echo Lingers

The impact of the intense, damaging Midwest derecho on Aug. 10, 2020, is still being analyzed and quantified.

This event left no fabric of society unscathed. Crops. Power grid. Grain storage. Outbuildings. Schools. Homes. Trees. Collectively, they form the tapestry of Mid-America agriculture and society.

Scientists and engineers have developed formulas for putting a mathematical value on the power unleashed in this event. But, a usable benchmark for putting some clarity on the power of the storm is a tornado.

Take the EF-1 tornado. That storm has wind speeds of 86 to 110 mph. At this level, damage to mobile homes and other temporary structures becomes significant, and permanent structures can suffer major damage to their roofs.

But, there's more. The upper end of that wind speed bracket matches that of a Category 2 hurricane. Such a storm produces the following damage features, according to the National Hurricane Center:

"Extremely dangerous winds will cause extensive damage: Well-constructed frame homes could sustain major roof and siding damage. Many shallowly rooted trees will be snapped or uprooted, and block numerous roads. Near-total power loss is expected with outages that could last from several days to weeks."

Those definitions offer details that match the impact of this derecho. No matter which comparison one selects, the blockbuster August 2020 derecho etched a new entry in the extreme storm vocabulary to join the term "bomb cyclone" from March 2019. And, as with the losses in that event, the impact of the summer derecho is powerful and long-lasting -- all the way through the end of this farming year.

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