When the peak of the annual glacial outburst flood hit early Wednesday morning, Aug. 13, in Juneau, newly installed flood barriers stacked along the Mendenhall River largely prevented flooding of the nearby residential area.
The flooding reached a record-breaking 16.65 feet at 7:15 a.m., but nearby homes, businesses and three schools were mostly spared. By that same afternoon, Juneau officials announced the flood threat was over. Officials reported there were no rescues or emergency evacuations during the flooding.
There was some flood damage to a bridge, which had already been closed to the public and was undergoing repairs.
Residents reported some seepage through the semi-permanent HESCO barriers — sand-filled, 4-foot-high containment baskets — into neighboring yards and homes, and some streets were flooded through water rising through storm drains.
About 90% of homes in the flood zone had no damage and only six of 846 residences were seriously damaged by the record glacial lake outburst flood, according to a preliminary assessment presented Friday, Aug. 15, by city officials.
Israel Katzeek helped his brother-in-law monitor his home in the Mendenhall Valley, on Lakeview Court and Meander Way, across the street from homes adjacent to the river. On Wednesday morning, water levels rose through the storm drains filling the intersection to about a third of the way up their driveway.
“At the peak, it was deep enough on this corner for paddleboarding, believe it or not. I wasn’t paddleboarding, but neighbors were,” he said.
They had prepared a two-foot wall of sandbags around the front of the home. Katzeek’s sister and her children had evacuated, but he and his brother-in-law stayed to monitor the house. Last year, the house had some partial flood damage to the garage so this year, the family took extra steps, with a sandbag barrier.
Many homes on the street had sandbags and plastic liners along garage doors.
Talking around midday on Wednesday as the flood waters were subsiding, Katzeek described what it felt like.
“Definitely relief. We were kind of bracing for the worst, obviously, with the barriers and elevating things and evacuating. It’s like ‘relief’ is just like the best way to put it,” he said.
Researchers and local officials have been analyzing data to better prepare for flood risks. It appeared that work was paying off.
This year, Katzeek said the emergency preparedness effort and alerts were helpful. “I think the neighborhood was well informed. I think there was better advance notice about the dam breakage at Suicide Basin,” he said. “Like thoughtful advisories in place well in advance of the flooding.”
The Mendenhall Glacier’s ice-dammed lake burst Tuesday morning, Aug. 12, prompting an emergency alert and following evacuation advisory for some downriver Mendenhall Valley neighborhoods. Waters swelled throughout the night, carrying trees, debris and glacial melt swiftly downstream.
Since 2011, the area has seen flooding from Mendenhall Glacier outburst events, as global climate change accelerates ice melting, more precipitation and increased flooding. Last year floods reached a then-record 15.99 feet, flooding the area and damaging more than 290 homes.
Throughout Aug. 13, the river continued to slowly recede; many onlookers came out to see the fast-moving, muddy waters carrying whole trees and debris downriver.
“The barriers are, by and large, holding together. We are seeing a small amount of seepage in the HESCO barriers in certain locations, and that’s still very much being assessed,” said Ryan O’Shaughnessy, director of emergency programs for the City and Borough of Juneau, at a news conference on Wednesday morning.
The two-and-a-half-mile levee was built earlier this year using barriers provided by the U.S. Army Corps of Engineers. The 466 property owners in the flood zone were asked to pay nearly $6,300 each to cover 40% of the city’s installation and maintenance costs, the Juneau Independent online newspaper reported. The barriers are intended to protect homes from river levels up to 18 feet.
There were some reports of trees striking the barriers and causing damage, O’Shaughnessy said, and some were repaired or fortified with sandbags further, but the extent of damage is still being investigated.
Sabrina Grubitz, safety manager with the Central Council of the Tlingit and Haida Indian Tribes of Alaska, emphasized the flood barriers were effective. “We can definitely say that if the HESCO barriers were not placed, we certainly would have seen a considerable amount more damage than we saw now,” she said. “They certainly have been doing their job.”
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