A new study theorizes that there could be more frequent and more violent storms accompanied by increased flooding and erosion in the Yukon-Kuskokwim Delta over the next 50 to 100 years due to climate change. The study by researchers from the U.S. Geological Survey and the University of Alaska used remote sensing technology along with traditional knowledge and observations from local Native people.
Alaska scientists used satellite images to look through clouds during storms and for the first time could see how far tidal flooding on the Yukon-Kuskokwim Delta extended inland. It was much farther than they imagined.
“It’s really extensive, it can go just about 20 miles inland during these really large storm events. So it covers a very large portion of the outer Delta,” said Jorgenson.
That’s Torre Jorgenson, a landscape ecologist and adjunct professor at the University of Alaska Fairbanks and co-author of the study. Scientists examined storm-flooding events in the Bering Sea region of western Alaska from 1913 to 2011 and found that the largest events occurred in autumn and were associated with high tides and strong southwest winds. The data allowed them to map and document the extent of the region’s flooding for the first time. Jorgenson’s projections show sea level could rise 1-3 feet in the region over the next 100 years and that the region will likely see an increase in the frequency of flooding in coastal areas to a monthly basis.
“The study also looked at the retreat of sea ice”, Jorgenson says, because it dampens the affects of storm surges in the winter. A delay of freeze-up of the Bering Sea during the winter could allow big storms and significant surges to extend into December and January. Dr. Craig Ely is a Research Wildlife Biologist with the U.S. Geological Survey and co-author of the study.
“Over a couple of days what happens is the tide comes up and then the wind pushes the tide inland even more. And then the winds are so high the tide doesn’t get a chance to leave and so the water just basically builds up over a couple of days. You know I’ve been out in some of the smaller storms when we’ve been kind of stranded out there and there’s just no low tide, it just keeps getting higher and higher,” said Ely.
Winter storms could have huge impacts: freshwater habitats converting to salt water, heavy sediment smothering vegetation, low lying permafrost plateaus collapsing, and villages eroding away.
81-year-old Leo Moses, of Chevak, was born about 30 miles South in Kashunik where he remembers a huge flood changed everything.
“And then after the flood had gone, for some years, the village itself started to sink. I think it was that the permafrost underneath the village was melting so it had nothing to hold it up and it started sinking it,” Moses.
The flood forced the village to move to old Chevak in the mid 1940s when Moses was about 7. The BIA then moved the village to what is now Chevak. Moses says he has no doubt he’s seeing climate change.
“Yeah, I’m seeing climate change every year. Man, the permafrost is going. Eventually we won’t have any permafrost. Ice up north, the ones that never used to melt start melting and there’s more water. What kind of future we have, I have no slightest idea,” said Moses.
Jorgenson points to the village Newtok, the first modern western Alaska village to initiate their own relocation, to Nelson Island, due to climate change. Jorgenson says warming temperatures and increased flooding will impact the Y-K region in his lifetime.
“I’m anticipating that most of the permafrost in this region will disappear in the next 30-50 years and storm surges help accelerate this loss by killing the vegetation,” said Jorgenson.
Both Ely and Jorgenson say their work provides a baseline on which more science can build. The findings of the study are in the most recent issue of the journal, Arctic.