A vocabulary of landscape — a landscape of words
1190 entries
derecho
A derecho is a windstorm that travels in a straight line rather than turning, produced by a long-lived complex of thunderstorms pushing a wall of cold downdraft air ahead of it. To qualify under the standard definition it has to run gusts of at least 58 miles an hour along a damage path of at least 250 miles. Afterward the trees all lie the same way, which is the field mark that separates it from a tornado.
Etymology
The word was coined in 1888 by Gustavus Hinrichs, a physics professor at the University of Iowa, who had been studying a windstorm that crossed the state in 1877 and had been calling such events Iowa squalls for want of anything better. He took the Spanish word for straight ahead and set it deliberately against tornado, which comes from the Spanish for turning. The pair was the whole point: one storm twists and the other one does not.
Notes
The term was used a little in the 1880s and then dropped out of the literature for nearly a century, until two meteorologists at the national severe storms center, Robert Johns and William Hirt, revived it in a 1987 paper and set the quantitative criteria still in use.