By April Garbuz, Wilton High School

A spot on the Deerfield River, at the base of Salmon Falls in Shelburne Falls, Massachusetts, is the site of the largest pothole on record. Formed at the conclusion of the last “Glacial Age,” the glacial potholes were carved when rushing rocks created a drilling, whirlpool effect.

Single Pothole

As a result of the constant whirling of the granite stones, the potholes formed in a symmetrical and round shape.

Glacial Potholes

The Glacial Potholes began to form when the Deerfield River first started to flow over these rocks 14,000 years ago.

Layers of rock from different time periods

When the last glaciers of the Glacier Age melted, the Connecticut River Valley was flooded, creating Lake Hitchcock. It increased the flow of the Deerfield River which carried stones, sand, and mud. The rocks and sand began to erode the hard metamorphic rock.

More potholes

The potholes continue to be formed during the snow melt when water levels rise and the millstones (still found in the smaller potholes) are whipped into swirling whirlpools.

Several Potholes

The round holes were ground down by the rocks in the river that were swept up in the whirlpool of water.

View of potholes

As the glaciers receded, fifty separate potholes ranging from 6 inches to 39 feet in diameter were formed.

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April Garbuz is a TalkingScience summer intern and a junior at Wilton High School. She loves science, debating, acting, and swimming. Ultimately, she'd like to be a research scientist.