The Mendenhall River flood near Juneau, Alaska, the state capital, reached a record-breaking crest of 16.65 feet on the morning of Wednesday August 13 after a massive glacial outburst sent debris-filled water rushing into neighborhoods. The National Weather Service (NWS) confirmed it was the largest event of its kind on record, surpassing last year’s crest of 15.99 feet. Officials urged residents in the 17-foot lake-level inundation zone to evacuate until an “All Clear” was issued.
The flooding, triggered by the sudden release of water from Suicide Basin above the Mendenhall Glacier, forced the closure of major community facilities, including the Mendenhall Valley Public Library and Diamond Park Aquatic Center. Roads were also blocked, with the Mendenhall Loop Road (Back Loop Bridge) shut down until water levels recede below 12 feet and safety inspections are complete. The Red Cross opened an emergency shelter for displaced residents.
The FAA issued a Temporary Flight Restriction to allow safe aerial monitoring and potential rescue operations. Authorities warned that the danger extended beyond the high water levels. “There is a lot of debris in the river. Please stay away from the river. It’s very dangerous right now,” said Andrew Park of the NWS. “If you get in that water, you’re not going to make it out of there.”
According to the U.S. Geological Survey, glacial lake outburst floods are unpredictable events that can cause major destruction. As glaciers continue to melt, officials warn these hazards may become more frequent and severe, demanding increased monitoring and preparedness.
