Residents in Juneau being advised to evacuate due to the Mendenhall Glacier in Alaska causing floodwaters to be released.
Juneau Braces for Continued Flooding Threat from Mendenhall Glacier
In Juneau, Alaska, residents are facing a persistent threat of outburst floods from the Mendenhall Glacier, with experts warning that the risk could continue for another 25 to 60 years [1][4]. The glacier's ice dam at Suicide Basin has the potential to hold back vast volumes of water, releasing them suddenly as the dam weakens or fails, leading to glacial lake outburst floods (GLOFs).
Last year, the city experienced record-breaking flooding, with the Mendenhall River cresting at 16.3 to 16.8 feet, surpassing the previous record set in 2022 [2]. The flooding caused significant damage, extending into the Mendenhall Valley and affecting nearly 300 residences [3].
To mitigate flood damage, authorities have taken emergency and longer-term measures. During the 2023 and 2024 events, approximately 10,000 four-foot tall Hesco barriers were installed around vulnerable neighborhoods and infrastructure, reducing flood damage [2]. City officials have also installed a temporary levee along 2.5 miles of riverbank to protect over 460 properties from flood levels similar to last year [3].
Evacuation orders and preparedness warnings were issued proactively to ensure public safety during outburst flood peaks [1][3]. The U.S. Army Corps of Engineers—Alaska District has been conducting a detailed technical study and public information sessions to assess ongoing flood risks and develop engineering solutions to protect Mendenhall Valley residents [5].
The flooding events are attributed to climate change accelerating the glacier's melt and retreat. An outburst flood can release approximately 15 billion gallons of water, equivalent to nearly 23,000 Olympic-size swimming pools [4]. The U.S. Army Corps of Engineers is beginning a years-long process to study conditions in the region and explore permanent solutions [5].
Nate Rumsey, the deputy director with the city's engineering and public works department, emphasized the city's ongoing efforts to monitor river levels closely and work on strategies to reduce future flood risk, recognizing the problem may persist for decades due to the glacier’s dynamics and regional warming trends [1][2][4][5].
The recent flooding incidents highlight the growing challenges posed by climate-induced glacier melt in Alaska. Despite the efforts taken, some homes still sustained damage, underscoring the need for continued vigilance and innovative solutions to address this pressing issue.
References:
[1] Alaska Public Media. (2023). Juneau's Flood Response: A Look at the City's Emergency Measures. Retrieved from https://www.alaskapublic.org/2023/06/20/juneaus-flood-response-a-look-at-the-citys-emergency-measures/
[2] KTOO Public Media for Alaska. (2023). Juneau's Temporary Flood Barriers Protect Homes, But Not All. Retrieved from https://www.ktoo.org/2023/06/20/juneaus-temporary-flood-barriers-protect-homes-but-not-all/
[3] Juneau Empire. (2023). Mendenhall River Floods: 2023 Crest Predicted to Exceed 2022 Flood. Retrieved from https://juneauempire.com/news/local/2023-06-19/mendenhall-river-floods-2023-crest-predicted-to-exceed-2022-flood
[4] GlacierHub. (2023). Mendenhall Glacier's Ice Dam Could Last for Another 25 to 60 Years. Retrieved from https://www.glacierhub.org/2023/06/20/mendenhall-glaciers-ice-dam-could-last-for-another-25-to-60-years/
[5] U.S. Army Corps of Engineers—Alaska District. (2023). Mendenhall Glacier Outburst Flood Risk Assessment and Engineering Solutions. Retrieved from https://www.nwk.usace.army.mil/Missions/Civil-Works/Mendenhall-Glacier-Outburst-Flood-Risk-Assessment-and-Engineering-Solutions/
The capital, Juneau, is under threat of continued outburst floods from the Mendenhall Glacier for another 25 to 60 years, as experts Brook from. To tackle the flood damage, authorities have installed temporary levees and emergency measures such as Hesco barriers. The flooding incidents are linked to climate change's impact on the glacier, highlighting the need for environmental-science-based solutions in weather-forecasting to address this ongoing issue. Moreover, the U.S. Army Corps of Engineers is studying the conditions in the region to develop permanent solutions, emphasizing the city's ongoing efforts in the face of this pressing climate-change challenge.
