In Alaska, warmer days can bring catastrophic flooding as frozen rivers break up

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Spring comes late to western Alaska and brings a mix of anxiety and anticipation. Citizen scientists use traditional knowledge to predict river breakup and flooding for dozens of remote communities.

Transcript

ADRIAN FLORIDO, HOST:

When spring finally arrives in southwest Alaska, people are eager to get outside. But longer, warmer days can bring catastrophic flooding as frozen rivers break up. Emily Schwing reports.

(SOUNDBITE OF FOOTSTEPS ON ICE)

EMILY SCHWING, BYLINE: Every Thursday, Mark Leary walks across the frozen Kuskokwim River in Bethel to measure how thick the ice is.

MARK LEARY: I'm going to measure in three spots. That's what I've been doing every week.

(SOUNDBITE OF ICE PICK HITTING ICE)

LEARY: You should probably stay behind me (laughter).

SCHWING: OK, I'll stay behind you (laughter).

Dark, grayish blue spots and lots of hairline cracks in the ice mean it's weakening. Leary works with Bethel's search and rescue crew. He's wary of having me along because I don't know this river like he does.

LEARY: I grew up in that house right over there on the bank, so...

SCHWING: OK.

LEARY: ...The river was always there, and we were always trying to figure out when we could get on it and when we could get - when we had to get off it.

(SOUNDBITE OF DRILLING THROUGH ICE)

SCHWING: When he finds a good spot, Leary bores a hole straight down with a long, spiraling drill bit.

(SOUNDBITE OF WATER SLOSHING)

SCHWING: Then he drops a weighted measuring tape down the hole.

LEARY: So this was 32 inches last Thursday. Now it's 29.

SCHWING: Leary is part of a network of local observers that help the National Weather Service and the state monitor flooding potential during the spring. Chunks of thick ice can jam up and cause problems.

CELINE VAN BREUKELEN: The ice stream flooding tends to be the greatest source of either major or moderate or just very devastating floods in Alaska.

SCHWING: Celine van Breukelen is a hydrologist with the National Weather Service.

VAN BREUKELEN: If we're trying to predict the likelihood of ice jams or where ice jams will form, that's not something that we can model from the office. It's something that we really have to see from the air.

(SOUNDBITE OF PLANE ENGINE)

SCHWING: Thanks to local knowledge about the river, van Breukelen knows exactly where to fly to look for signs of ice jams and flooding.

UNIDENTIFIED PILOT: Downriver transition east upriver 1,000.

VAN BREUKELEN: Ooo (ph). OK. So that's our first pressure ridge that we've seen this year.

SCHWING: Oh, right there. I see it.

VAN BREUKELEN: Yeah.

SCHWING: Yep.

VAN BREUKELEN: And that's where we've started to actually see some movement. Over here, like, on the sheet of ice that's right underneath us, you can see some of the shear lines where the ice has, like, been forced up on the sides.

SCHWING: Two enormous slabs of ice have slammed into one another. Spring is here, but one flight over the river and ice thickness measurements all winter doesn't tell the river's whole story.

VAN BREUKELEN: So one of the things I've really learned is to ask more questions and do more listening than talking, especially when speaking with elders and locals.

SCHWING: Local elders like Alaska native Robert Lekander.

ROBERT LEKANDER: In the old days, you'd hear it night and day that the ice would be making noise like - I guess, maybe like a train going down, just (imitating crashing sound).

SCHWING: Lekander has spent nearly eight decades living along the Kuskokwim River, and he says the effects of climate change are clear. The ice is thinner.

LEKANDER: It's down 3 feet thick. Before, it was, you know, 5 to 6 feet when I was growing up.

SCHWING: But Lekander says there's one thing that hasn't changed out here - the river is still a way of life.

For NPR News, I'm Emily Schwing in Bethel, Alaska. Transcript provided by NPR, Copyright NPR.