West Virginia has only one natural lake: Trout Pond, a two-acre body of water near Wardensville in Hardy County. But did you know that the western portion of West Virginia was once covered by a massive proglacial lake that extended far into Ohio? If you did, impressive! You’re part of a very small fluvial minority. If you didn’t, you’d best fasten your geologic seatbelt, because it’s time for some good ol’ fashioned lake-splaining.
About 2 million years ago, the Quaternary glaciations of the Pleistocene epoch began an icy cycle of advancement and retreat that undoubtedly played a massive role in shaping the Appalachian landscapes we adore today. Some 750,000 to 1 million years ago, the Earth-pulverizing ebb and flow of these glaciers—some up to three miles thick—resulted in the damming of the region’s ancestral rivers and the subsequent creation of Lake Tight. This sprawling body of water, named for geologist William G. Tight, covered an estimated 10,000 square miles in western West Virginia, southeastern Ohio, and northwestern Kentucky (see Figure 1).
Prior to the Pleistocene era, most rivers in the northeastern United States did not follow the familiar watercourses we know today. The Teays River, the ancestral river that became the modern New and Kanawha rivers, flowed northward from its headwaters in North Carolina through Virginia, West Virginia, Ohio, Indiana, and Illinois before joining the ancestral Mississippi River system. According to Dr. Steven Kite, emeritus professor of geology and geography at West Virginia University, neither the Ohio River nor the Great Lakes existed during this time. “There were huge changes in all these drainages when half the continent was covered with ice,” says Kite. “One by one, these watersheds were deflected and rerouted south around the natural ice dam of the glaciers.”
As the Pleistocene glaciers advanced through Ohio, their relentless grinding pushed sediments further south with each new glaciation. These sediment deposits piled up in the region’s mountainous valleys, some reaching 400 feet in depth. While these glaciers never actually reached into present-day West Virginia, their presence heavily influenced the hydrology of the Mountain State.
When the icy curtain of the glaciers finally reached the Teays Valley in Ohio, the river hit a literal wall and began back-filling its mainstem as well as its numerous tributaries well into western West Virginia. Unlike the narrow, glacially carved Finger Lakes in New York State, Lake Tight resembled the meandering, dendritic reaches of Summersville Lake, which was formed when the Gauley River was dammed in 1966. In 2018, James Erjavec, geologist and GIS analyst, created a map of Lake Tight, estimating it to have a volume of 268 cubic miles—nearly 2.3 times the volume of Lake Erie—and an average depth of 140 feet, with some pockets nearing 300 feet in depth.
Geologists still debate whether the natural dam that blocked the Teays was a sheer wall of ice or a wall of sediment from the outwash of meltwater coming off the glacier. Dr. Kite, however, thinks it was likely a combination of the two. “I can’t prove this, but I think both situations were right at different times,” he says. “Early on, it might have been the sediments coming off the glacier that caused the valleys to fill up and block the drainage, but as the glacier kept advancing, the ice itself could have become the dam.”
Perhaps most fascinating is the discovery of paleomagnetically reversed sediments in areas once covered by Lake Tight. These magnetized particles have been dated to a period from 790,000 to 880,000 years ago, when Earth’s magnetic poles were reversed. “As these unconsolidated sediments settled out of the water column, the magnetic particles aligned with the Earth’s magnetic field at that time,” says Kite. “Some of those particles retained that core magnetic orientation, which shows that they were deposited when the North Magnetic Pole was in the south.”
The glacial damming of the Teays River effectively ended its reign as one of the major river systems on the North American continent. But, as Kite explained, the truly dramatic hydrological changes that shaped our modern rivers began when the last ice age ended. “What people overlook is the period after Lake Tight, which is when it really starts to get exciting,” he says. “Not only is the water getting rid of that sediment, but it’s also cutting down the bedrock even further. We owe a lot more of our topography to what went on after Lake Tight than from the lake itself.”
The rerouting of the region’s major river systems cut fresh channels, forming new river canyons in Appalachia’s unstable terrain. Although consolidated sediments aren’t anywhere near as hard as bedrock, water has but one destiny: take the path of least resistance. “It was easier for these rivers to cut through the bedrock than to flow over top of the sediment,” says Kite. “Around Teays Depot, there’s 180 feet of sediment that blocked the Teays River, so what we now know as the Kanawha River ended up taking the route that we see today.”
The next time you find yourself in western West Virginia, take a look at the seemingly countless hills and hollows that extend as far as the eye can see. Stop for a minute and picture a sea of ice in the distance. Then imagine a colony of giant ground sloths browsing among the shores of those hollows, flooded with deep, blue water from the lake before time.
Dylan Jones is publisher of Highland Outdoors and is a self-described geology nerd. He tries his best not to lake-splain in a condescending way when sharing his stoke for West Virginia’s fascinating geologic history.