Juneau Braces for Record-Breaking Glacial Flood: What You need to Know
Updated August 13, 2025
Juneau, Alaska is currently facing a significant flood event as Suicide Basin, a lake formed by glacial melt, overflows its natural ice dam – the Mendenhall Glacier. Experts predict the Mendenhall river will reach record-high levels today,prompting evacuation orders for residents in vulnerable areas. This isn’t a sudden crisis; it’s a recurring phenomenon escalating due to glacial retreat.
Understanding the Situation
The root cause lies in the changing landscape around the Mendenhall glacier, located just 12 miles from Juneau. Years ago, a smaller glacier receded, creating Suicide Basin.
Here’s how the flooding unfolds:
Snowmelt & Rainwater Accumulation: Throughout the warmer months, the basin fills with snowmelt and rainwater.
Glacial Dam: The Mendenhall Glacier acts as a natural dam, holding back the water.
Overflow & Release: Eventually, the water level rises to a point where it leaks under or over the glacier, releasing a surge into Mendenhall Lake, then the Mendenhall River, and ultimately downstream towards Juneau.
Escalating Risk: This process has been occurring since 2011, with 2023 and 2024 experiencing back-to-back record floods. Last August, the river crested at 16 feet (5 meters), exceeding the previous year’s peak by a foot.
Record-Breaking Flood Imminent
Current forecasts indicate this year’s flood will surpass all previous records. Meteorologist Nicole Ferrin stated, “This will be a new record, based on all of the information that we have.” Experts anticipate water levels between 16.3 and 16.8 feet (4.96 to 5.12 meters).
On monday, Alaska Governor Mike Dunleavy issued a state disaster declaration. This action acknowledges the severity of the situation, confirming that water levels in Suicide basin have reached or exceeded those observed during past record-breaking events. The declaration, released by the Division of Homeland Security and Emergency Management, highlights the imminent threat to the Mendenhall River and surrounding neighborhoods.
Preparedness & Response
Fortunately, authorities have been proactively preparing for this event. Over two miles of flood control barriers have been installed along the Mendenhall River. The water release from Suicide basin began yesterday morning, and officials are closely monitoring the situation.
Sabrina Grubitz, public safety manager for the Central Council of the Tlingit and Haida Indian Tribes of Alaska, emphasized the level of readiness. “We are prepared for this situation. We’ve been preparing for this situation,” she said,leading a unified local government task force.
A Wider Context: Increasing Flood Risks
This event in Juneau underscores a growing trend across the United States. Deadly floods have impacted communities nationwide this summer, bringing renewed scrutiny to the accuracy of FEMA’s flood maps. Many argue these maps are outdated and fail to adequately reflect current risks.
This situation highlights the critical need for:
Updated Infrastructure: Investing in modern flood control infrastructure.
Accurate Mapping: Developing and maintaining precise flood risk assessments.
Community Preparedness: Empowering communities with the knowledge and resources to prepare for and respond to these events.
Resources:
Associated Press: https://apnews.com/article/alaska-glacial-flooding-dam-0454d452237bbd81d5d32ce5fe25471f
* Alaska division of Homeland security and Emergency Management: [https://ready.alaska.gov/Documents/PIO/PressReleases/2025.08.10_PRESS%20RELEASE%20-%20Governor%20Dunleavy%20Issues%20Disaster%20Declaration%20in%