Massive Glacial Dam Burst Causes Devastating Flood in Juneau, Alaska
JUNEAU, Alaska — A glacial dam burst in Juneau, Alaska, over the weekend, resulting in the destruction of several homes and the displacement of residents as flooding ravaged the area. The incident occurred when the Mendenhall River’s water levels rose to an unprecedented degree due to the bursting of a snow-and-ice dam, a phenomenon known as a jökuhlaup. While this phenomenon may be little-known in the United States, researchers warn that glacial floods like these could pose a threat to approximately 15 million people worldwide.
The incident left a trail of destruction in its wake. A gray, two-story home with white trim collapsed and slid into the river, while a neighboring condo building teetered on the edge of a bank, its foundation already eroded by the rushing waters. Amanda Arra, a resident whose home still precariously hung over the river bank, described her fear as she witnessed trees falling one after another into the water.
The flooding was triggered by a side basin of the Mendenhall Glacier, which acts as a natural dam for rain and melted snow. As water accumulated in the basin during the spring and summer, it eventually burst out from beneath the glacier and flowed down into Mendenhall Lake and the Mendenhall River. While sporadic flooding from the basin has occurred since 2011, this event was particularly astonishing due to the rapid and powerful surge of water. The river’s flows rose to about 1 1/2 times the previous highest recorded levels, washing away sensors that had been placed by researchers to study this glacial outburst phenomenon.
The effects of the flood were devastating. Two homes were completely lost, and a third suffered significant damage. In total, eight buildings, including those that fell into the water, have been condemned. However, some structures may be salvaged with substantial repairs or bank stabilization. Fortunately, there have been no reports of injuries or fatalities.
While climate change plays a role in melting glaciers like the Mendenhall, scientists caution that it is not directly responsible for these individual floods. The complex relationship between climate change and glacial floods makes it difficult to predict and prepare for such events. Celeste Labedz, an environmental seismologist, highlights the variability in timing and volume of glacial outburst floods, making them challenging to forecast.
According to a study published in Nature Communications, more than half of the people at risk from glacial outburst floods reside in India, Pakistan, Peru, and China. Past events have led to devastating consequences, such as a 1941 flood in Peru that claimed up to 6,000 lives. However, glacial lake outburst floods in recent years, like the one in British Columbia, Canada in 2020, have caused significant damage but fortunately resulted in no human casualties.
The Mendenhall River area is particularly vulnerable to erosion due to its loose glacial deposits, leaving the ground easily susceptible to damage. Eran Hood, a professor of environmental science at the University of Alaska Southeast, emphasizes that the situation could have been much worse if heavy rains had coincided with the flood. He describes the damage inflicted by the flood as a wake-up call for the community.
Residents, such as Chris and Bob Winter, who have lived by the Mendenhall River for decades, now face the devastating reality of property damage and potential relocation. The couple’s house has flooded multiple times in recent years, and Chris Winter expresses concern about their future and the likelihood of being able to sell their property.
As scientists continue to study these glacial outburst floods, it becomes essential to raise awareness about the potential risks they pose to communities worldwide. With millions of people at risk, understanding and preparing for these unpredictable events will be crucial in mitigating their impact.
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Associated Press reporter Thiessen reported from Anchorage. Associated Press writer Gene Johnson in Seattle and researcher Jennifer Farrar in New York contributed to this report.