Did a Derecho Hit the Upper Thumb?

On the early morning of Thursday November 6th neighbors heard a commotion what could only be described as “sounding like a freight train” ripping sound their street. Within moments trees were failing and branches  over 9 inches in diameter were being hurled over 30 yards or more. It was over in seconds. When neighbors came out to explore it seems the damage was confined to a very small area comprised of three lots. A tree was down and damaged part of a garage while another took out a fence. There were similar reports of damage across the thumb.Bad Axe lost trees and experienced power outages. Schools were dismissed early.

The  residents of the  upper thumb witnessed microbursts spawned by the classic weather phnominon known as a Derecho. The derecho (pronounced similar to “deh-REY-cho”), is a widespread, long-lived wind storm. Derechos are associated with bands of rapidly moving showers or thunderstorms variously known as bow echoes, and squall lines

Although a derecho can produce destruction similar to that of a tornado, the damage typically occurs in one direction along a relatively straight path. As a result, the term “straight-line wind damage” sometimes is used to describe derecho damage. By definition, if the swath of wind damage extends for more than 240 miles (about 400 kilometers), includes wind gusts of at least 58 mph (93 km/h) along most of its length, and several, well-separated 75 mph (121 km/h) or greater gusts, then the event may be classified as a derecho.
The winds associated with derechos are not constant and may vary considerably along the derecho path, sometimes being below severe limits (57 mph or less), and sometimes being very strong (from 75 mph to greater than 100 mph). This is because the swaths of stronger winds within the general path of a derecho are produced by what are called downbursts, and downbursts often occur in irregularly-arranged clusters, along with embedded microbursts and burst swaths. Derechos might be said to be made up of families of downburst clusters that extend, by definition, continuously or nearly continuously for at least 240 miles (about 400 km). 

Information about derechos were taken from NOAA.


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