A rush of water unleashed by an ailing glacier has caused severe flooding in Juneau, Alaska, marking the second significant event in nearly a year. The Mendenhall River in the Mendenhall Valley reached record levels as more than 100 homes were damaged or impacted by the destructive flooding. City officials have described the flood severity as "unprecedented."

The flooding was a result of glacial lake outburst, which occurs when a lake of melting snow, ice, and rain drains rapidly after pooling up and overtopping the glacier that contains it. These outbursts have become more frequent since 2011 and are believed to be a consequence of climate change. Alaska, along with the rest of the Arctic, is warming at twice the rate of the rest of the planet, leading to the thinning or complete melting of glaciers like the Mendenhall and Suicide glaciers.

The Suicide Glacier, once a vast expanse of ice, now features an earthen divot that fills up each summer, resembling a bathtub. On August 1, the lake at Suicide Basin reached its limit, causing it to overtop the glacier. This came after an unusually wet July which received twice the normal amount of rain. By Sunday, it became clear that water from the lake was reaching the river, leading city officials to issue evacuation warnings to residents.

The water levels in the Suicide Basin lake dropped drastically following the outburst, plummeting over 400 feet, with more than 350 feet decreasing in just 24 hours. The rapid drainage resulted in the Mendenhall River reaching an unprecedented level of 15.99 feet on Tuesday morning. This was more than a foot higher than the levels reached last year, when homes collapsed into the eroded riverbank.

The extent of this year's flooding surpassed that of the previous incident, impacting areas deeper into the Mendenhall Valley. Streets were inundated with up to 3 to 4 feet of floodwater, and homes were surrounded by a milky expanse of water that reached vehicle hoods. Despite the destruction, no injuries were reported, and the city was able to provide emergency shelter to affected residents, with around 40 people seeking refuge overnight.

In response to the disaster, Alaska Governor Mike Dunleavy issued a declaration of emergency to support response and recovery efforts. He expressed gratitude that no casualties were reported and commended the exemplary efforts of emergency responders and managers in ensuring the safety of the residents.

Fortunately, the floodwaters have receded as the glacial lake is no longer full, and the Mendenhall River has returned to below flood stage, as reported by the National Weather Service in Juneau.

The destructive glacial lake outburst floods in Juneau serve as a grim reminder of the impact of climate change on vulnerable regions. It is crucial that measures are taken to mitigate the effects and protect communities at risk in the face of environmental challenges.

Disclaimer: This article was written based on information from the provided source, and it has been paraphrased and summarized in the writer's own words.