by Juneau, AK — Alaska Governor Mike Dunleavy has issued a state disaster declaration in anticipation of what officials warn could be a “catastrophic flooding event” from a glacial lake outburst flood (GLOF) tied to Suicide Basin, a side basin of the Mendenhall Glacier.
Proactive State and Local Response
The declaration follows a joint local emergency declaration by the City and Borough of Juneau and the Central Council of the Tlingit and Haida Indian Tribes of Alaska. Officials say hydrologic monitoring by the National Weather Service (NWS) and the U.S. Geological Survey (USGS) shows the basin’s water volume has reached or surpassed levels seen in previous record floods.
“A release is expected at any time. Flooding is likely to affect the Mendenhall River and surrounding neighborhoods in the Mendenhall Valley,” officials warned.
Governor Dunleavy emphasized the need for early action:
“By issuing this declaration before the flood occurs, we can position state resources and personnel in advance to support local and tribal governments in their efforts to protect lives, homes, and essential services. Our goal is to act early to reduce impacts and preserve community safety.”
Recent History of Severe Flooding
This proactive stance comes after two consecutive years of significant flood damage. The August 2024 GLOF caused extensive destruction to homes, public infrastructure, and utilities, prompting both state and federal disaster declarations.
Juneau City Manager Katie Koester noted the lessons learned from past events:
“This year is different. We’re not just responding – we’re ready. The HESCO barriers are in place, and we believe they will perform as designed, but our job is to plan for every scenario – especially in the face of what could be another historic flood event.”
Current Situation at Suicide Basin
The NWS reports that USGS instruments and cameras have detected the basin overtopping its ice dam, with icebergs being drawn toward the overflow channel. Historically, this stage can precede a major flood by up to six days.
Residents have been urged to complete flood preparations immediately. City officials have sent alerts via the Wireless Emergency Alert and Emergency Alert Systems, with a second alert planned when the basin begins releasing water. Printed evacuation notices are being delivered to homes in the 17-foot inundation zone.
What is a Glacial Lake Outburst Flood?
According to the USGS, a GLOF occurs when water stored in a glacial lake suddenly drains. These lakes often form in valleys left ice-free by retreating glaciers and can be dammed by ice, rock, or debris. Over time, the water pressure can breach the dam, unleashing a rapid, powerful flood downstream.
These events are highly unpredictable and have caused loss of life and infrastructure damage worldwide. Climate change adds uncertainty to the frequency and severity of these hazards as glaciers continue to melt.
Read Also: Heavy Rain and High Tide Trigger Flood Risk in Charleston, South Carolina
Community Preparedness
The Alaska State Emergency Operations Center is now fully activated, coordinating with local and tribal agencies on emergency permitting, public messaging, and readiness measures. Officials stress the importance of residents staying informed and following evacuation protocols if necessary.
“Suicide Basin is full and beginning to overtop,” reads an alert on the City and Borough of Juneau’s official site. “Flood expected. Follow emergency alerts and use the resources on this page to stay safe.”
The situation in Juneau serves as a stark reminder of the risks posed by Alaska’s dynamic glacial landscapes. Authorities say the coming days are critical for both preparation and monitoring.
How would your community handle such a sudden flood threat? Share your thoughts in the comments, and read more disaster preparedness stories at ibwhsmag.com.
