11 Future Voices in Geoscience- Undergraduate Research Posters

This session is for two-year college and four-year college and university students presenting research posters in any subdiscipline of geosciences. Posters and presentations will be judged for awards.

Monday, 18 May 2026
8:00 AM - 5:30 PM
Alvarado D/E

Impacts of Valley Floor Morphology on Long-Term Channel Migration in Yellowstone National Park

Paper number: 11-5
Program: Technical Sessions
Time: 8:00 AM – 8:00 AM

Authors

Abstract

Extreme flooding in northern Yellowstone National Park in June 2022 produced erosion that undercut and washed out Park roads and other infrastructure along the northeast entrance road. The June 2022 flood was the largest ever recorded in the Park, in some places exceeding the 500-year flood recurrence interval. Major floods also occurred in the Lamar Valley in 1918, 1974, 1996, 1997, and 2011. Historical airphotos record the last 70 years of change in the Lamar Valley at approximately decadal intervals, providing an untapped source of information about the position of the channels in three reaches with distinct valley floor environments. In ArcGIS, we mapped channel area and the position of the channel centerline on each air photo. We evaluated how major floods and valley floor morphology control rates of lateral channel migration on reaches along Soda Butte Creek, the Lamar River, and Slough Creek. On all reaches, significant changes in the position of the channel were observed to happen during periods of time with a large flood, but also periods of time without a large flood. This suggests that large floods are not the only control on when lateral channel migration occurs, and that valley floor morphology has a large impact on lateral migration. An anastomosing reach with wide valley floors on Soda Butte Creek has the highest rates of channel migration and the channel has occupied many different positions during the past 70 years. Reaches of Soda Butte in the most confined parts of the valley experienced very little lateral movement over time but a high magnitude of erosion in the 2022 flood. Along the Lamar River, reaches where the valley was widest similarly experienced the most channel migration and very little change where the channel is confined by glacial outwash deposits. Slough Creek experienced the most erosion during the 2022 flooding directly downstream of a bedrock confinement area, and low gradient reaches tended to be relatively stable over time with the exclusion of a large oxbow lake cutoff.

Geological Society of America Abstracts with Programs. Vol. 58, No. 4

doi: 10.1130/abs/2026RM-410688

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