Residents of low-lying villages in Alaska know exactly where their communities are most prone to flooding, but that information hasn’t always been accessible on a wider scale. New research helps compile more than 130 years of on-the-ground flood observations to help communities and outside agencies prepare for and predict future floods.
As fall storm season looms, so do storm-driven floods. Seventy-six percent of storm-driven floods in Western and Northern Alaska happen between September and November.
This year, in August alone, nine separate storms have pummeled the Yukon-Kuskokwim Delta in an incredibly early start to fall storm season. Mid-month, a series of three storms flooded homes, boardwalks and fuel tanks throughout the Kuskokwim Delta coast and up the Kuskokwim River. The highest summer wind speed since at least the 1970s was recorded on Aug. 16 at the Bethel Airport.
“It’s been a priority on my list for a long time to improve flood mapping in Alaskan villages,” said geologist Rich Buzard, who works for the United States Geological Survey, which is focused on flooding and erosion. “Most villages in Alaska don’t have adequate flood mapping, essentially, and that has led to several scenarios where flood preparation wasn’t as good as it could have been and communities have suffered.”
Buzard was the lead author of a University of Alaska Fairbanks study published earlier this year that looks at flood risk in communities along the western and northern coasts of Alaska by compiling and analyzing a database of hundreds of written accounts and observations going back to the late 1880s.
“The challenge was that in today’s age of mapping, and numbers, and models, and things, that information wasn’t translated into the language we use now,” Buzard said. “And so a lot of my work was gathering these observations, finding out the truth: which flood is actually the highest, what kind of impacts did it cause? Where did the water go? And then doing the math on how high that water is and where we put it on a map.”
There are two key issues the project tries to address. The first is that communities haven’t really been able to use or access their historic data when doing community planning or in identifying current and future flood risks.
“In my experience working on flooding and erosion in Alaska and then sharing the results in communities, a lot of times the response I get is like, ‘Hey, this seems really accurate to what we’ve been saying. It sort of validates our claims,’” Buzard said. “Communities use that information in project proposals and planning. Evidence, scientifically-backed evidence, goes a long way to getting a proposal approved. So I’m hoping that this type of work can help communities plan effectively and get things done, and hopefully move things forward in a way that maybe they’ve had roadblocks in the past.”
The second issue is to collect scattered flood data from around the region in one place so that it can be useful for agencies looking at floods and flood risks on a more regional scale. Buzard said that the research found that from Bristol Bay to the North Slope, there are around 2,000 structures that currently sit in what’s called the record floodplain, places where the highest recorded flood has touched before. The Bethel Census Area, which encompasses the Kuskokwim coast to far up the Kuskokwim River, has the most structures in the record floodplain of any part of the study area.
“With sea level rise, that just sort of increases the baseline,” Buzard said. “And so over time, smaller flood levels can become more frequent. And if a record flood were to come, it may have a higher chance of exceeding a previous record.“
In order to prepare for future storm-driven flooding, Buzard said that communities need to know exactly how much of an issue sea level rise might be.
“The sea level rise projections that are out now – by just adding those to the current record flood level, then by 2100 we’re seeing about 20% to 30% more structures in the floodplain than what we have today,” Buzard said.
As communities grow and build increasingly expensive infrastructure, Buzard said that taking flood risks into account becomes even more important.
“I think that the big shift that needs to happen is more thought about flood risk, basically, in planning and community development,” Buzard said. “And so that’s what we’re trying to create is tools, flood tools that people can use to make those plans so that our communities in the next 50 years won’t be facing the risks that we’re dealing with today.”
Buzard said that the research is a stepping stone for ongoing and future efforts by USGS, Alaska State Coastal Hazards Program, National Oceanic and Atmospheric Administration and the National Weather Service to advance flood mapping in Alaska.
“There’s a lot of work being done to improve flood mapping and incorporate climate change into that, and all of that work is supported by community observations,” Buzard said.
Some of that work involves trying to bring Alaska into USGS’s Coastal Storm Monitoring System, which can help predict coastal flooding and erosion. It’ll also include further community surveys of exactly what parts of structures are under threat from future floods. Many structures in Western and Northern Alaska are elevated above the ground. To understand flood exposure in a more detailed way, Buzard said that he’ll have to survey those first-floor elevations.
There’s also more work to be done with Buzard’s database of historic flood impacts. Right now, a lot of the data is in spreadsheets.
“For individual communities, they’re going to need the map, right?” Buzard said. “They’re still going to need context for how sea level rise could impact them.”
Buzard said that Typhoon Merbok, which hit Alaska’s west coast in 2022, left him scrambling to quickly produce maps that could identify flood risks. He had just finished the preliminary work for the project. And then in some communities, Typhoon Merbok met or exceeded the record flood level.
“If another large storm like that happens, we’re going to have a lot more tools and maps available so I don’t have to do that, like, overnight,” Buzard said with a laugh. “It’ll already be done, is my goal.”
Ultimately, Buzard said that this work is a testament to the importance of community monitoring and observations.
“When you read the news reports and scientific publications, they always talk about how Alaska doesn’t have very much data and that makes things very challenging, and so this work is demonstrating how we can get over that challenge,” Buzard said. “I have a flood history of over 100 years based on community observations, and we continue to use those all the time.”
And that database continues to grow, in part thanks to a new avenue for community flood monitoring: a private flood observations Facebook page monitored by the Alaska State Coastal Hazards Program, NWS and Buzard at USGS.
