Juneau officials are urging residents in parts of Mendenhall Valley to voluntarily evacuate ahead of a possible glacial outburst flood. Last year’s flood damaged over 290 homes in the valley, a suburban district near the Mendenhall Glacier, raising ongoing safety concerns.
City crews built temporary HESCO barriers to prevent future flooding, but these have never been tested under actual emergency flood conditions. The Glacier Recreation area, Alaska’s most visited tourist attraction, is preparing to close as water levels continue to rise near the glacier’s base.
Officials shut the Nugget Falls Trail on Monday, halting access to the most popular path in the recreation area. The US Forest Service, which operates the glacier site, did not attend Monday’s briefing due to staffing shortages after federal workforce reductions.
Late Sunday, Juneau cellphones blared with alerts as water began overtopping the ice dam holding the glacier’s seasonal lake. Hydrologists expect water will soon rush from the dam into Mendenhall Lake, then surge into the Mendenhall River toward neighborhoods.
The first flood occurred in 2011, but worsening climate change has made subsequent events increasingly destructive for Mendenhall Valley residents. Aaron Jacobs of the National Weather Service said the ice dam is 13 feet lower than last year but holds equal water.
The lake in Suicide Basin contains around 16 billion gallons, weighing 67 million tons, equivalent to 335 loaded container ships. Recent heavy rainfall over the past week has added to the danger of rising water levels in Mendenhall Lake and River.
