Glacial Rift Causes Major Floods Wreaking Havoc in Alaska

A break in the Mendenhall Glacier caused a flash flood that has wreaked havoc near Juneau, Alaska, where several structures and homes have been destroyed.

The flash flood was recorded in Suicide Basin, a lateral basin on Mendenhall Glacier, located about 12 miles north of the Alaska state capital.

Flooding, triggered after a dam containing a glacial lake burst, has destroyed several structures along the Mendenhall River, according to Servicio Meteorologico Nacional.

Trees and debris are currently fouling the river.

Video taken by resident Sam Nolan shows a multi-story structure collapsing into the river. “It was really sad to see, but all we could do was stand there and watch,” the man said according to News.

Other videos taken by residents show debris and trees floating in the Mendenhall River near the Juneau International Airport.

On Sunday morning, two 6-unit condominium buildings at 4401 Riverside Drive, next door, were condemned. Signs posted on the buildings said they were “unsafe for human occupancy.”

The National Weather Service described record flooding of waterways and low-lying areas, along with flooding “in areas that have never before seen that phenomenon.”

The 14.97-foot crest far exceeded anything Juneau has seen since its annual flash floods, which began in 2011.

“There is no comparison. We are two feet above our last record,” said meteorologist Nicole Ferrin, with the National Weather Service in Juneau.

At 4:15 am Sunday, it was down to about 12 feet, still nearly two feet above moderate flood level. By 7:30 a.m., the level had dropped 10.24 feet and was still falling rapidly.

And by 10:00 a.m., when the flood warning was scheduled to end, the Weather Service wrote that “it was already Flooding is not expected to pose a threat, but hazards persist in and near the Mendenhall River.”

The flooding has closed several roads in the region, including bridges, according to the city of Juneau.

The city's emergency operations urged residents to stay away from the river for the duration of the flood.

From Saturday through Sunday morning, the Juneau power company announced it would shut off power to some neighborhoods as they flooded. Earlier in the morning, the utility said it was restoring power to neighborhoods as the waters receded.

In its news release, the city said the Mendenhall River Bridge in the Back Loop was safe to use, but engineers still needed to evaluate the pedestrian bridge at Dimond Park.

Meanwhile, the state Department of Environmental Conservation asked residents to report any oil tanks that may be been swept away by flooding by calling 1-800-478-9300.

The risk of flooding from melting glaciers will increase as the climate warms, according to a study published in Nature Climate Change in 2021.