Residents in Juneau, Alaska, have been dealing with significant flooding after a dam by the Mendenhall Glacier broke, causing the most severe flooding the city has seen from this annual occurrence. Approximately 100 homes and some businesses were damaged as floodwaters rose rapidly overnight on Tuesday. Cars were seen floating in chest-high water as individuals hurried to evacuate. By Wednesday, the waters had started to recede, and the river level was dropping.
The flooding was a result of a nearby smaller glacier retreating over a decade ago due to climate change, leaving a basin that fills with rainwater and snowmelt each summer. During times of increased pressure, as happened recently, the water finds its way under or around the ice dam formed by the Mendenhall Glacier, flowing into Mendenhall Lake and eventually into the Mendenhall River.
Since 2011, instances of flooding near Mendenhall Lake and Mendenhall River have occurred intermittently, with last year’s floods causing substantial damage to homes and property. This week’s flooding, however, was unparalleled, leaving residents shocked as they attempted to salvage belongings and clear out waterlogged homes.
Although the basin formed due to glacial retreat, climate change has a minimal impact on the year-to-year variations in flooding volumes in Juneau, according to Eran Hood, an environmental science professor. The glacial flooding serves as a stark reminder of the global risk posed by bursting snow-and-ice dams, a phenomenon known as a jökuhlaup, which could potentially affect millions worldwide.
Juneau, a city of around 30,000 residents in southeast Alaska, accessible only by air and water, is already facing a housing shortage that may limit available temporary accommodations for flood victims. The city also has few rental car agencies for those whose vehicles were impacted by the flooding.
Residents like Alyssa Fischer recounted being alerted to the flooding by her father via FaceTime early Tuesday, prompting her to evacuate with her children and pets to a shelter at a local middle school. While Fischer was fortunate to have limited property damage, she expressed concerns about the future and the safety of her community in the face of recurring floods.
The Mendenhall River reached a record height of 15.99 feet (4.9 meters) during this recent flood, surpassing last year’s levels by more than a foot and extending further into the Mendenhall Valley than before. The National Weather Service had warned of rising water levels last week, prompting city officials to advise residents to prepare for flooding, evacuate, and seek shelter as needed. Fortunately, there were no reported injuries, and Governor Mike Dunleavy issued a disaster declaration to support response and recovery efforts.
