Every summer, meltwater builds up in Suicide Basin, an ice-dammed lake above Mendenhall Glacier. When the water pressure becomes too high, the water bursts through, flooding the river and the city. The 2024 flood was one of the worst in over a decade and caused millions of dollars in property damage. It also displaced residents from their homes with little warning. Although the U.S. Geological Survey collects stream gauge data from lakes and glaciers, the National Weather Service provides weather forecasts, and the City and Borough of Juneau shares flood alerts, many of these information sources can be hard to understand and/or scattered across multiple websites.  

A new interactive flood dashboard is available to help Juneau residents prepare for glacial outburst floods from Suicide Basin. The Juneau Flood Dashboard, developed by researchers at the University of Alaska Southeast and partners with support from the Alaska CASC, brings together flood forecasts, historical data, and inundation maps on an easy-to-use platform. The tool shares maps, alerts, and allows users to see how different water levels might affect specific areas of the Mendenhall Valley. Users can search for local addresses, including their own, to see expected street-level impacts – or they can simply hover a cursor over the map to reveal expected floodwater depths.  

The site also includes frequently asked questions (FAQs), historical flood data, and explanations of how glacial floods form, giving important context for those unfamiliar with this unique type of flooding. For instance, unlike typical floods that are caused by rain, glacial outburst floods can’t be predicted from typical weather cues. They could occur at the end of a warm sunny week. 

The dashboard was designed to support quick understanding, even under stress. Residents can use the dashboard to prepare emergency plans, identify risky locations, and better communicate about risks to each other. The dashboard is a timely adaptation tool for community awareness, safer responses, and stronger resilience as climate-driven events continue to affect Southeast Alaska. 

This work was supported by the Alaska CASC project “Improving Forecasts of Glacier Outburst Flood Events.” 

Explore the Juneau Glacial Flood Dashboard and learn more about the “hidden water of Suicide Basin” from the Alaska CASC.