On Sunday, Alaska’s Governor Mike Dunleavy declared a disaster due to the “immediate threat of catastrophic flooding” linked to the Glacier Lake Explosion Flood (GLOF) from the Mendenhall Glacier Side Basin.
This decision follows a local disaster declaration made by the city and borough of Juneau, assisted by the Central Council of Trigint and the Haida Indian Tribe.
Officials are preparing for a potentially unprecedented flood event from the suicide basin located above the Mendenhall Glacier.
“Hydrological monitoring by the National Weather Service (NWS) and the US Geological Survey (USGS) confirms that water levels in the basin have reached or surpassed those seen during past flood events,” authorities noted. “Releases are expected soon, which could impact the Mendenhall River and nearby Mendenhall Valley areas.”
This year follows two years of severe flooding, with the August 2024 GLOF causing extensive damage to housing and public infrastructure, prompting state and federal disaster declarations.
“By declaring this emergency in advance, we can assist local governments in safeguarding lives and services,” Dunleavy explained. “Our aim is to act early to minimize the impact on the community.”
The Alaska Emergency Business Center has been reactivated to facilitate local and tribal responses, including coordination among various departments, public messaging, and preparation for any necessary actions.
Mayor Katie Coaster of Juneau remarked, “We’re not just reacting this year; we’re prepared. Our plans include all possible scenarios, especially given the likelihood of another historic flood. This declaration empowers us to act swiftly.”
The NWS mentioned that webcams and laser tools revealed concerning ice blockages in the basin, suggesting that water levels might drop soon.
As water pressure builds in the basin, officials are urging residents to complete their preparations. Flooding is imminent, and alerts will be sent out as situations evolve.
What is a glacial lake explosion flood?
Glacier Lake Explosion Floods (GLOFs) are distinct from typical flooding from heavy rainfall. They occur when ice dams formed by glaciers in valleys give way, allowing lake water to pour downstream.
According to USGS, these lake systems can suddenly release their accumulated water, leading to unpredictable, potentially destructive events. As global temperatures rise, the risks associated with these glacial lakes may evolve, which poses further questions about future impacts.
