The year 2026 marks the 250th anniversary of the Declaration of Independence. Cardinal News has embarked on a three-year project to tell the little-known stories of Virginia’s role in the march to independence. This project is supported, in part, by a grant from the Virginia American Revolution 250 Commission. Find all our stories from this project on the Cardinal 250 page.The term “derecho” crashed into the minds of many Virginians on June 29, 2012, when the hottest day in a generation was followed by tree-toppling gusts that knocked power out to over a million utility customers and killed 10 people in the commonwealth, just a portion of its 800-mile, $3 billion march of damage from Lake Michigan to the Chesapeake Bay.But the term “derecho” was coined for a long-lasting straight-line windstorm some 134 years earlier by University of Iowa scientist Gustavus Hinrichs in 1888. Iowa is a more frequent derecho target than Virginia — Hinrichs had studied data from an 1877 windstorm in the Hawkeye state. Iowa suffered a derecho with wind gusts up to 140 mph on Aug. 10, 2020. (Top recorded wind gusts were near 90 mph in the 2012 derecho.)Hinrichs’ term did not come back into much use until some scientific publications in the 1980s, focusing on bowing storm clusters propelled rapidly forward by a colder pool of air that develops to the rear of them from storm downdrafts. It’s been only in the past quarter-century, inflamed by a few particular events with noteworthy impact in various regions or sometimes a large metropolitan area (most recently Houston), that the term “derecho” has come into popular usage on media and social media.But, of course, Hinrichs didn’t invent the derecho — he merely labeled it. They have been occurring on occasion throughout history.Is it possible a derecho played a substantial role in American independence a century before Hinrichs defined the windstorm?It is a tantalizing possibility to consider that the same kind of windstorm that brought so much fright and discomfort — and some outright death and destruction — to Virginians in 2012 might have helped the American Colonists defeat the British on Virginia soil and water 241 years earlier.The York River widens considerably near Yorktown, as shown here in November 2019. A sudden windstorm is said to have scattered British flatboats crossing the river during a British attempt to escape the need to surrender in October 1781. Photo by Kevin Myatt.The evidence for a derecho-like event, at least, is fairly strong in and near Yorktown in mid-October 1781, when Gen. Cornwallis and over 8,000 British soldiers under his command were hemmed in by American forces on land and the French fleet at sea.David M. Ludlum’s book “The Weather Factor” describes the situation in which Gen. Cornwallis attempted to evacuate his troops from Yorktown across the York River to Gloucester Point on Oct. 16-17, 1781. Three round trips involving 16 flatboats were considered sufficient to accomplish the task, and the first back-and-forth was made without incident.Then, the weather started getting rough, and Cornwallis’ plans were tossed.“But at this critical moment, the weather from being moderate and calm, changed to a most violent storm of wind and rain and drove all the boats, some of which had troops aboard, down the river,” Cornwallis wrote in a post-battle report, Ludlum writes.Ludlum notes that other reports of the storm mention thunder and lightning occurring, and American brigadier general Elias Dayton describing it as “almost as severe a storm as I ever remember to have seen.”Because the flatboats were blown to the southeast — two them far enough downriver to be captured by the French in Chesapeake Bay — Ludlum surmises the wind was from the northwest and identifies a “line squall thunderstorm” as the likely culprit. Meteorologists would more often call this a “squall line” today.The shelf cloud from a squall line’s outflow fills the sky over eastern Roanoke County in July 2022. British forces in 1781 would not have seen anything like this approaching, as the storm struck suddenly at night. Photo by Kevin Myatt.Conditions had been mostly warmer than normal for several days before the potential squall line, and then turned unseasonably cold afterward. That would be highly suggestive of conditions in which a squall line would have developed ahead of a cold front plowing into the warmer air.But could the squall line have been a true “derecho,” a long-lived line or cluster of storms with nearly continuous damaging outflow winds covering at least 240 miles?Putting aside slightly different definitions even today of what constitutes a “derecho,” there simply aren’t enough weather records from the time along such a track to say one way or the other if damaging winds covered a sufficient distance to be considered a derecho.The June 29, 2012, derecho swept a path across the Ohio Valley to the Chesapeake Bay. A squall line may have traced at least part of this track in October 1781 to thwart a British military evacuation of Yorktown, through it is doubtful it was as long-tracked or powerful as this highly memorable storm event. Courtesy of National Weather Service.The reaction in the diaries and battle accounts by officers and regulars on both sides of the conflict suggest that the storm was something extraordinary, not unlike the reactions of many Virginia residents on the evening of June 29, 2012. But it could well have been that the gusts roiling the York River were fairly localized, not covering a long distance.An argument against the 1781 Yorktown tempest being a derecho would be its timing. October isn’t a common time for derechos to occur, as most happen in the summer and feed on unbroken instability from daytime heating.And of course there was no Doppler radar in 1781, so seeing the storm hitting Yorktown as some kind of multicolor bow or line shape was as far out of the imagination of anyone involved in the siege and surrender as landing on the moon would be.Capturing British redoubts, the restored earthworks of one shown here in November 2019 at Yorktown Battlefield, was a key to the stages of the Battle of Yorktown for American forces. Photo by Kevin Myatt.What isn’t in dispute is that the squall thwarted Cornwallis’ last, best chance to escape the encirclement of American troops around his position combined with the blockade of Chesapeake Bay by the French fleet, and he was forced to surrender two days later.“A violent windstorm arose at midnight, however, scattering the boats and forcing an abandonment of the escape,” states “History of the Siege” on the National Park Service’s Yorktown Battlefield web page. “Realizing the situation was hopeless, Cornwallis sent forth a British drummer on October 17, followed by a British officer with a white flag and note indicating a request for a cease fire.”A “line squall” that may or may not have been a derecho helped secure victory for the Americans in the decisive battle of the Revolutionary War.James S. Baillie depicts British Gen. Cornwallis handing his sword to American Gen. George Washington, with the French fleet lined up in the Chesapeake Bay beyond, after the Battle of Yorktown in October 1781. This scene apparently never occurred, as Cornwallis is reported to have cited illness and left the sword surrender to another general. Courtesy of The Smithsonian.Want more weather news? Or Virginia history?We have regular newsletters on both subjects. You can sign up for those or any of our other free newsletters below: The Daily Everything we publish, every weekday The Roundup A roundup of our 10 most popular stories each week, sent Saturdays at 7 a.m. Cardinal Weather In-depth weather news and analysis on our region, sent Wednesdays West of the Capital A weekly round-up of politics, with a focus on our region, sent Fridays Your Weekend Spread your wings this weekend with our go-to guide for celebrations, festivities, and other events happening in our region, delivered every Thursday at noon. Cardinal 250 Revisiting stories from our nation’s founding. 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