Residents and local officials in Juneau, Alaska, are preparing for possible flooding from the Mendenhall Glacier after new measurements showed higher water levels in a nearby basin. This type of event, called glacier outburst flooding, occurs when water pressure forces a sudden release from a basin blocked by ice. It has been a serious concern since 2011 because of the glacier’s natural ice dam, which holds water from seasonal rain and melting snow. The National Weather Service reported that the basin reached 1,353 feet (412 meters) last Friday, only 15 feet (4.6 meters) below the danger point. Studies revealed that large floods can release up to 15 billion gallons of water, a truly significant volume.

Authorities placed about 10,000 temporary barriers along 2.5 miles of riverbank to protect over 460 properties. This preventive measure aims to reduce damage and keep people safe. Officials warned that debris in high water may create hazardous conditions. The U.S. Army Corps of Engineers started a long-term study. Some residents expressed frustration over the slow process, while experts called for collaborative planning. Such efforts could be beneficial and effective in protecting the Mendenhall Valley from repeated flooding for decades.