Basalt Columns -- Clearwater River Dike Bike Path, Lewiston ID - Glacial Lake Missoula Flood Features on Waymarking.com

Once you know what Glacial Lake Missoula Flood features to look for, you see them everywhere! This excellent example of basalt columns is along the US12 Dike Bypass at the trail access east of the Railroad drawbridge.

These columns are in a basalt deposit along the river that is part of the City of Lewiston's "back of the house" operations. The city Garbage Transfer Station is on top of the deposit, the city's wastewater treatment plant is nearby, and the city's treated wastewater is returned to the Clearwater River at a pumping station in front of these basalt columns.

These basalt columns are part of the Columbia River Basalt Group that stretches to the Pacific Ocean, the result of massive repeated lava flows that covered parts of 4 states that began 17 million years ago and ended 6 million years later.

In the intervening millions of years before the Ice Age occurred 20,000 years ago, these columns were slowly weathered, broken, and covered with soil and vegetation. Once the Ice Age began, this area experienced advancing and receding glaciers, which created "rock flour" and deposited more soils and rocks on the columns.

Once the ice dam that created Glacial Lake Missoula formed, these columns were under water, perhaps for many decades. Periodic Lake Missoula floods caused torrents of rushing water to scour and sculpt the land, exposing long-buried basalt columns to the elements that are still visible today.

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Date Logged Log User Rating   02/24/2022 Benchmark Blasterz visited it