Title: U.S. Geological Survey monitoring of glacial lake outburst flooding in Juneau, Alaska
Date: February 25, 2026
Time: 11:00 a.m. (Alaska Standard Time)
Presenters: Jeff Conaway, Associate Center Director for Water, Ice, and Landscape Dynamics and Jamie Pierce, Hydrologic Technician
About the Talk: Since 2011, the Mendenhall River in Juneau has experienced annual glacial lake outburst floods (GLOFs) originating from Suicide Basin, posing significant risks to homes, infrastructure, and public safety. The 2024 flood reached record levels and impacted over 300 homes, making it the most severe event to date. In 2025, another record-breaking flood occurred, but damage was limited to 47 homes thanks to new mitigation measures installed by the City and Borough of Juneau, including a temporary levee and HESCO barrier system. These improvements represent a major step forward in reducing flood impacts, though flooding remains an ongoing hazard.
To support forecasting and emergency response, the USGS Alaska Science Center actively monitors conditions using satellite-modem cameras, laser tracking, and real-time water sensors in the glacial-dammed lake and along the Mendenhall River. This data enables the National Weather Service to predict flood timing and magnitude, allowing local officials to make informed decisions about evacuations and road closures. It also informs the design and evaluation of mitigation measures to further reduce risk. These efforts are part of a collaborative partnership between USGS, the City and Borough of Juneau, the Alaska Department of Transportation and Public Facilities, and the Army Corps of Engineers. Continued investment in monitoring technology and infrastructure is critical to protecting lives and property as these annual flood events persist.
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