Some residents in Juneau, Alaska are facing evacuations as meltwater from the Mendenhall Glacier poses a growing threat of unprecedented flooding in the area. The National Weather Service (NWS) has issued an urgent flood warning, highlighting that water from glacial outburst is flowing into the Mendenhall River, endangering local homes. Authorities have been monitoring the situation closely, with officials alerting residents to potential evacuation for days. On Tuesday, it was confirmed that water had started to escape from an ice dam, leading to expectations of flooding in the near future.
Situated about 12 miles (19 km) outside of Juneau, the popular tourist destination, Mendenhall Glacier, has become the center of concern as rising water levels reached an alarming 9.85 feet (3 meters) on Tuesday. Although this was below the major flooding threshold of 14 feet, reports by Wednesday showed the levels had surged above 16 feet, indicating a crest and a likely new record. "Based on all the data we have, this will set a new record," noted Nicole Ferrin, a meteorologist with the NWS during a press briefing on Tuesday.
The Juneau city website has provided explanations regarding glacial lake outbursts, likening the phenomenon to a bathtub overflowing when its plug is pulled. The outburst occurs when melting snow and ice, combined with rain, rapidly drains from a glacial lake, potentially leading to catastrophic floods. In response to this imminent danger, Alaska Governor Mike Dunleavy declared a state disaster on Sunday, citing the "serious threat of catastrophic flooding which has been a recurring problem in Juneau since 2011." The area has seen severe flooding previously, with many homes destroyed in last year’s deluges.
Furthermore, scientists report that the world's glaciers are retreating faster than ever, leading to an increase in significant meltwater glacial lakes. These lakes have been shown to be expanding in both size and number worldwide since 1990. The natural barriers—comprised of ice and rock—that contain these lakes can collapse unpredictably, resulting in sudden, uncontrolled floods. Researchers anticipate that climate change will further elevate the frequency of such outburst floods in the future, highlighting the complexities of past trends and individual flood causes.
