29-22 Investigating Blowout Activity in Response to Falling Lake Michigan Levels

Session: Undergraduate Research, Part II (Posters)

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Coastal dunes along Lake Michigan have shown activity related to changing lake levels, creating opportunities for study in recent years as lake levels rose (starting in 2014) to an extreme high (in 2020) and then fell to average levels (in 2025). This study investigates dune characteristics and activity within a blowout (Site A) at Hoffmaster State Park in Michigan and compares results with a nearby blowout of similar size (Site B). The study location is an exposed beach-dune system on the east coast of Lake Michigan where rising and high lake levels demolished a prominent foredune and eroded a dune ridge. Total station surveying, GPS mapping, and field observations were used to document blowout characteristics. Erosion pins, sand traps, wind measurements, and observations were used to measure dune activity. Autumn 2025 measurements at Site A were compared with Site B data collected over multiple years. Results for dune characteristics show substantial erosion from a distinct area of bare sand making up a large amount of the blowout which is 8.5 meters high and 45 meters wide. The blowout is active, with wind carrying the sand from the beach into the blowout, and from erosion areas within the blowout to deposition areas on the leeward slope of the dune. Comparison with Site B shows that since lake levels began falling, a substantial ridge has been building up at the lakeward opening of each blowout, deflation area slopes are steeper, and wind-blown sand is transported well beyond the slipface toe. Understanding blowout responses to changing lake levels is vital to understanding how dune processes play a role in coastal sediment budgets and shoreline management strategies.

Geological Society of America Abstracts with Programs. Vol. 58, No. 1, 2026

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