Widespread river flooding sweeps away at least 2 structures; Alaska’s capital city declares emergency

JUNEAU, Alaska (KTUU/Gray News) - The City and Borough of Juneau issued a declaration of emergency on Sunday following a glacial lake outburst flooding event that swelled waters to record levels.

At least two structures were swept up into rushing waters, and other structures were evacuated on Saturday after the flooding event filled Mendenhall Lake and Mendenhall River to dangerously high levels.

The Mendenhall River banks “remain highly unstable.” officials said.

“All members of the public are strongly advised to stay away from the river to ensure safety and avoid obstructing response efforts,” the City and Borough of Juneau wrote in a release.

According to the National Weather Service, river waters reached a record-high of 14.97 feet on Saturday night, much higher than the previous high water mark of 11.99 feet from 2016.

Incidents of this type of flooding in Juneau are a regular summer occurrence since 2011 but have never caused so much damage. Meteorologist Andrew Park with the National Weather Service in Juneau said they forecasted the flooding event to be smaller — around 12 feet — and it’s unclear at the moment why the flooding went above that.

“We had trees just skirting down the river. A house was floating down the river swept away. A significant amount of debris to make this a pretty serious situation and deadly situation,” Park said. “It’s a new river. So we had people in pack rafts and kayaks going down the river today, and it’s totally inappropriate to be doing that. It’s a really dangerous situation, so definitely a brand new river.”

The flooding occurs when water levels rise and then release from Suicide Basin, a reservoir that sits along the edge of the Mendenhall Glacier, rapidly filling Mendenhall Lake and River.

“And then when you get enough pressure to build up, the water force — the hydrostatic pressure on the lake against the glacier — eventually something has to give and it will actually go under the glacier, get into the lake and start increasing water levels,” Park said.

While relatively few structures border the lake, dozens of houses line the banks of the roughly six-mile-long river.

Multiple people captured on camera the collapse of one house going into the river.

City and Borough of Juneau Deputy City Manager Robert Barr said he’s not aware of any injuries or missing individuals as of Sunday afternoon.

“Right now, we are engaged in street cleanup work. We’re doing a lot of communication,” Barr said.

He said it is too early to determine how much property damage has been done, but estimated the number is already in the millions of dollars. The City and Borough of Juneau said it is working with property owners to track damages.

City officials said in a release they’ve been in contact with all residents who were asked to evacuate to confirm shelter availability.

“I just feel really bad for all these people on the river that now aren’t going to have a place to live,” Juneau resident Matthew Creswell said on Sunday at the Mendenhall River bridge on Back Loop Road.

Creswell said his neighborhood did experience some flooding. But the flooding, he said, has since gone away and his front yard is now just muddy.

“We all know each other at some time or another and everybody is connected,” Creswell said. “It’s sad to see your neighbors lose their property like that,” Creswell said.

On Monday at 6 p.m., Juneau Assembly members will meet to discuss the declaration. Meanwhile, city officials are working on cleanup efforts following the flooding and are continuing to advise residents to avoid the river bank, as it remains unstable.

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