Ancient Lake Missoula Shorelines -- Clarkston WA - Glacial Lake Missoula Flood Features on Waymarking.com

These ancient shorelines (also called strandlines) are a feature of the modern landscape carved into basalt by Glacial Lake Missoula beginning 20,000 years or so ago, and ending with the end of the Ice Age.

The best place to see these strandlines is along the Port Road in Clarkston WA, although they are also visible from along the Clearwater Dike Hike and Bike Trail in Lewiston ID.

The different lines show the different levels of Lake Missoula, which ebbed and flowed over time as periodically Lake Missoula's ice dam broke and massive flood discharges occurred. When the ice dams reformed, the lake filled again, over and over.

Source: (visit link)

"Glacial Lake Missoula Strandlines
Ice Age Floods National Geologic Trail

Ancient shorelines or strandlines of Glacial Lake Missoula are visible as perfectly parallel horizontal benches ground into hillside slopes around Missoula. . . .

These shoreline benches cut by wave action in the lake recorded various lake levels as the ice dam blocking the Clark Fork River far upstream on the Idaho border repeatedly failed and refilled 40 times or more. Some speculate that as the ice-age waned each successive ice dam that reformed was smaller and failed under less pressure from a lower lake level than the one before, leaving behind its bench as a record of the successively lower ancient lake shorelines. Most agree they record winter still-stands in rising lake levels over time."

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Date Logged Log User Rating   02/22/2022 Benchmark Blasterz visited it