Urgent "iceburst" flooding warning in Alaska triggers disaster proclamation
The residents of Juneau, Alaska, are bracing for an imminent threat of a Glacier Lake Outburst Flood (GLOF) from Suicide Basin, a side basin of the Mendenhall Glacier, which could occur within the next 1 to 6 days [1][2][3].
The National Weather Service (NWS) and U.S. Geological Survey (USGS) have confirmed that the volume of water in Suicide Basin has reached or exceeded levels observed during prior flood-of-record events [2][3]. This development follows local disaster declarations by Juneau and tribal authorities, and a state disaster declaration by Alaska Governor Mike Dunleavy [2][3][5].
The 2025 Juneau GLOF Unified Command, led by the City and Borough of Juneau (CBJ), Tlingit & Haida tribes, and the U.S. Coast Guard, has activated final response preparations covering flood mitigation, emergency shelter, transportation staging, and public notification measures [1]. A Wireless Emergency Alert and Emergency Alert System notification was sent to all Juneau cell phones after the NWS detected overtopping on August 10. Further alerts will be issued when the basin begins releasing water [1].
The threat of a GLOF is not new to the area. A similar event a year ago caused widespread damage to homes, public infrastructure, and utilities, prompting state and federal disaster declarations [4]. Video posted on social media two years ago showed towering trees behind a home falling into the rushing Mendenhall River as the water ate away at the bank, eventually causing the home to collapse into the river [4].
To try to curb the impact of future flooding, Juneau and the Army Corps of Engineers have installed more than two miles of flood control barriers along the Mendenhall River [4]. However, the event remains unpredictable and dangerous, with flood control measures offering only partial protection.
Residents are advised to stay informed through official channels such as the CBJ alert system, NWS updates on Suicide Basin status, and state emergency resources [1][5]. The top priority remains the safety of people and infrastructure in the flood zone.
References:
[1] City and Borough of Juneau (CBJ) website: https://www.juneau.org/ [2] National Weather Service Juneau office website: https://www.weather.gov/jnu/ [3] U.S. Geological Survey (USGS) website: https://www.usgs.gov/ [4] Alaska Dispatch News: https://www.adn.com/ [5] State of Alaska Emergency Resources: https://www.alaska.gov/admin/adm348/emergency-response/
- As the weather-forecasting agencies like the National Weather Service (NWS) and U.S. Geological Survey (USGS) predict a potentially catastrophic Glacier Lake Outburst Flood (GLOF) from the Mendenhall Glacier's Suicide Basin, residents of Juneau are advised to follow news regarding climate-change events, weather updates, and environmental-science information together with alerts from official channels.
- The increasing volume of water in Suicide Basin, which has surpassed levels observed during prior flood-of-record events, highlights the importance of weather-forecasting and the need for the general public to stay updated on such happenings, especially when they have serious implications for their immediate environment and community.
- With the actions of flood mitigation, emergency shelter planning, transportation staging, and public notification measures already instigated as part of the final preparations by the 2025 Juneau GLOF Unified Command, it becomes crucial for the residents to be well-informed of the current state of Suicide Basin to safeguard lives, property, and infrastructure.
