An outburst of flooding from a lake dammed by Juneau’s Mendenhall Glacier has once again wreaked havoc on nearby neighborhoods, damaging at least an estimated 100 homes. This recurring hazard stems from a lake formed in a basin left behind by a retreating glacier, which fills with rainwater and snowmelt during the spring and summer. As pressure builds, the water forces its way out through channels beneath Mendenhall Glacier.
Since 2011, this phenomenon has periodically caused flooding of streets and homes near Mendenhall Lake and Mendenhall River. Last year, a dramatic incident saw a two-story home swept away by floodwaters, prompting some residents to reinforce the riverbank near their properties. This year's flooding, while less dramatic in terms of structural damage, was more widespread, affecting hundreds of homes, including some outside expected flood areas.
Officials are still assessing the extent of the damage, with over a hundred homes confirmed affected and the possibility of multiple hundreds. The National Weather Service reported that the Mendenhall River crested at 15.99 feet, higher than last year's crest, causing significant water levels in Mendenhall Valley. Streets were inundated with 3 to 4 feet of water at some points, although erosion was reportedly less severe than the previous year.
Fortunately, no injuries were reported, and Governor Mike Dunleavy issued a disaster declaration to support response and recovery efforts. The river level dropped quickly after peaking, providing some relief. Increased monitoring and technological advancements allowed for better preparation this year, with warnings issued in advance and an emergency shelter opened for affected residents.
