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Post-flood meeting breaks down science, flood stories
- Ellie Ruel
- 2 hours ago
- 4 min read
Residents share experiences, ask about future flood outlook
By Ellie Ruel
Juneau Independent
This year’s glacial lake outburst flood may have peaked lower than expected and released more slowly than previous years due to a cool, dry summer, according to University of Alaska Southeast hydrologist Eran Hood during a Juneau Flood Solution Advocates meeting at the Mendenhall Valley Public Library last Thursday.
Hood said based on preliminary observations, his best guess is that a subglacial network of channels wasn’t as well primed or centralized before the release began on Aug. 11. The Mendenhall River crested at 14.7 feet on Aug. 13, the lowest level seen during a full Suicide Basin release in the past four years.
“When that water starts coming in from the basin and it's forcing its way under the glacier, it has to do the work through the friction to create the drainage pattern,” Hood said.
Those systems normally transport glacial melt through the system daily, and friction from the water moving over ice helps to widen and centralize channels, he said. Typical base flow for the river in mid-August is usually around 2,500 cubic feet per second (cfs), but was lower this year at closer to 1,700-1,800 cfs.
“That means there's less water moving under the glacier, and so my guess is that the system was not very well primed,” he said.
According to Hood, initial analysis shows there was about 48,000 acre-feet of water in the basin this year, down 4% from last year. More ice was in the basin from a few calving events leading up to the release, he said as he pointed to a photo of blue icebergs in an empty basin.
“Just the calving itself, although it expands the extent of the basin, it doesn't really increase the volume until you melt the ice that capped off there,” Hood explained. “So that I think at this point is the one wild card. It's just the potential for (lateral) expansion.”
He noted the ice difference likely didn’t contribute to changing conditions.
“I don't think that it had to do with the amount of ice because the amount of ice is not that much different percentage-wise,” he said.
The research team will continue to analyze data and plans to present it to the public at some point this fall. A smaller fall release is predicted, similar to last year.
Hood cautioned the audience against reading into trendlines about future flood outlook based on a small amount of data. Suicide Basin has caused outburst floods since 2011, but they were small compared to the full-basin releases that began in 2023. Hood said the science team is still trying to understand why the releases transitioned from partial to fully emptying the basin.
“One issue I had with the messaging last year after last year's flood was we had three data points and they were going upward, and it's like the message was that the flood gets bigger every year,” he said. “Now we have a fourth data point. It didn't get bigger, right? So we know it doesn't get bigger every year. Does that mean it can't get bigger in the future? It doesn't mean that. So there's just a lot of variability.”
Before Hood’s presentation, more than 20 residents shared their feelings before and after the flood. Words like anxious, tired, prepared and relief echoed around the room.
“It's kind of frustrating. It felt like we were packing up and moving before the flood. Three or four weeks doing that, and then a couple weeks after the flood, unpacking again,” said Mark Miller, a Long Run Drive resident. “I was optimistic before the GLOF, and pleased it went as well as it did.”
Debbie Penrose-Fischer, the leader of the neighborhood advocacy group, thanked community volunteers for their work that she said went unthanked by officials, righting what she called a “misstep.”
“When I listened to the Assembly meeting, I was crushed that I didn't hear one mention of the community,” she said. “I saw a group of people with perseverance, teamwork, and facing each other (to) face one more year of adversity, invasion into your property, stress, fear, financial loss, preparation that's too hard physically to do.”
She listed contributions to the “Eyes on the River” livestream and gift baskets delivered to View Drive residents as examples.
Malachi Thorington, a View Drive resident who stayed during the flood, said the package was appreciated. He said his household has experienced one to two feet of water over the last three years.
“With this year being kind of a grace period, we’ve been relieved for a change,” Thorington said. “This year I was running solo, so it was a breath of fresh air to have some even knocking, especially as we were just kind of watching with bated breath.”
Lori Stedmen, a Marion Drive resident, said her family has lived by rivers for generations. She said she’s hopeful about a long-term solution after years of stress from the flood.
“I think it's gonna be really beneficial for a lot of folks that are having life-changing situations happening, that's affecting their health, that have affected their everyday life right now,” she said. “I've got a financial situation here, and I built my house here on the river, but not knowing what was going on in the future. So I can't just get up and move.”
• Contact Ellie Ruel at ellie.ruel@juneauindependent.com.
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