Glacial flooding measured in real time at Juneau, Alaska

USGS streamgages show that flooding conditions are now underway, live cameras offering real -time opinions on the USGS Hivis website. The floods caused by glaciers have become an annual threat since 2011, with record floods in the past two years that have had an impact on more than 300 houses and threatened public security.

The USGS works with the City and the District of Juneau, in Alaska, the Ministry of Transport and Public Installations, and the US Army Corps of Engineers to monitor the conditions and provide real -time data on the versions of Lake Glacier. A lake of the backdrop of glacier forms when a glacier blocks the natural drainage of a valley, trapping water which ends up crossing or around the ice barrier.

“Our surveillance in real time gives emergency managers the prior warning they need to protect the residents of Juneau,” said Jeff Conaway of the USGS Alaska Science Center. “This information allows officials to make critical decisions concerning evacuations and road closings before flooding waters reach dangerous levels.”

The USGS monitors the conditions in the Damné of the glaciers using two cameras and a laser to follow the water and the ice levels. This information is used by the NWS to predict when and how the floods will seriously occur, allowing emergency managers to anticipate dangerous conditions and make informed decisions on evacuations and road closings.

Downstream from the glacier, the USGS streaming on Lake Mendenhall measures water temperature and elevation of water every 15 minutes. A decrease in the water temperature combined with the increase in lakes levels helps to distinguish the release of water from the Dammé lake from the glaciers from the regular runoff from precipitation. By working with the USACE, the USGS has installed three streams on downstream bridges on the Mendenhall river to measure the height of the water and the flow.

The cameras installed at the bridges offer real -time views of the river and will update the USGS Hivi page during the flood. The USGS will measure the depth of the bottom of the river at the bridges after the flood to help those responsible to determine if the bridges are safe for reopening.

This complete surveillance data helps resource managers and emergency stakeholders to protect life and goods. Data can also improve flood forecasting models and assess the effectiveness of flood control measures that the city and the juneau arrondissement installed along the river.