Alaska News

Slow, steady melt makes breakup a 'mushout' on Kuskokwim and Yukon rivers

BETHEL -- So far this breakup season, it's a "mushout" on Alaska's two longest rivers, the Yukon and the Kuskokwim.

But even as river ice slowly melts in place, state emergency managers and federal river experts are continuing a long tradition of monitoring for signs of ice jams and floods. They call the effort River Watch, a partnership between the state and the National Weather Service that dates back more than 30 years.

Teams started flying over the Kuskokwim River on Friday and along the Yukon on Saturday to look for rising water levels, ice jams and new pressure ridges along the ice pack. They provide information straight back to communities by radio, phone calls and Twitter, said Amanda Loach, a state emergency management specialist leading the Kuskokwim River Watch team working out of Bethel.

"Good morning, Akiak," said Peter Atchak, a Bethel volunteer flying with the team on Tuesday. Atchak, the former longtime leader of Bethel Search and Rescue, relayed river reports to villages by marine-band radio, sometimes speaking in Yup'ik. "We are right above you." he told Akiak. There was ice down river, he reported.

"There's no way to get below your village," he warned anyone thinking of boating down river. "It's completely backed up."

Still, he said, the ice was weakening. The water levels were low. Managers say the risk of floods is minimal.

"Quyana," a village leader from Akiak answered, thanking him.

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"Roger that," Atchak said.

Up and down the Kuskokwim, so far, so good, said hydrologist Crane Johnson with the National Weather Service, part of the Kusko River Watch team.

"We're still in a situation where the ice is riding in place," he said. It is melting where it is, a quiet sort of thermal breakup that some call a "mushout." Atchak says the ice rotting around some lower river villages is "original ice," not ice on the move from upriver.

In years with big snows and thicker river ice, breakup is dynamic -- a roaring, rumbling grind of ice that can jam and cause floods, hydrologists say.

This year, there was low snow along the Kuskokwim and it's already melted except in the mountains. Long stretches of the river already are open. But still there's a whisper of danger.

In bends, around islands and in areas of deeper, colder water, ice is holding. Some eager river travelers already have put in their boats despite the risk of big chunks of ice breaking loose upriver.

On Tuesday morning's mission down to the Johnson River and then up to Tuluksak, the River Watch team saw ice stretching across the mouth of the Tuluksak River. Johnson, the hydrologist, spotted new pressure ridges -- indicating an area to watch -- between Akiak and Akiachak. But Kwethluk, along with other villages, was "looking high and dry," said Loach, with the state Division of Homeland Security and Emergency Management.

On the Yukon River, the ice went out Monday in Dawson City, up in the Canadian Yukon, but so far is still holding in Alaska.

The past winter along much of the Yukon, snow levels were normal, unlike on the Kuskokwim. But with temperatures gradually rising, the melt is happening slowly, said Celine Van Breukelen, a hydrologist with the National Weather Service in Anchorage.

In 2009, truck-sized ice smashed homes in Eagle during a record flood on the Yukon. In 2013, there was more flooding on the Yukon.

Floods typically come when the temperatures jump up and the snow melts before the ice degrades, she said.

"There's all this meltwater and it has nowhere to go," Van Breukelen said. "It ends up pushing on these very, very strong ice sheets and the ice sheets break up violently or become jammed and back up water."

Floods can happen even in low-snow years, like in 2011 when about a quarter of the homes on the upper Kuskokwim village of Crooked Creek were destroyed.

This year, hydrologists and emergency managers have their eyes on a stretch of ice in the Kuskokwim that starts downriver from the village of Kalskag. A giant ice jumble formed there last November at a curve called Coffee's Bend after a fall thaw and then a second freeze-up. Ice from upriver that broke free now is staging behind it.

But open leads on each side are allowing water to flow past, lessening fears of flooding, Loach said.

"It wasn't bank-to-bank solid jumbled ice at Coffee's Bend," she said.

Sheets of ice cover miles of the Kuskokwim including around Aniak, where the ice has been moving in fits and starts since Sunday. Ice slid downstream, a gap opened up, but the big slabs didn't give way.

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"Ice Yawns at Aniak," Bethel Search and Rescue reported on its website.

By Tuesday evening, the river was rising at Aniak, but not enough to cause worry of flooding, Loach said.

Even if there's not a risk of flooding, the flights provide vital information to village residents who depend on the river for travel and are stranded during freezeup and breakup, Atchak said.

No one is riding snowmachines on the rotting river ice anymore. But residents are eager to get out in boats. In past years, rescuers have had to drop supplies to river travelers who boated to a camp, then were cut off when moving ice hemmed them in, Atchak said.

He is preparing to put his boat into the river as soon as upriver ice melts out or goes past. He and his son snag driftwood to heat their homes in the winter. Not much wood is being reported in the river so far, though.

On Bethel's riverfront, where much of town is protected from flooding by a seawall, small chunk ice and slivers of needle ice tinkle in the moving river. But just around the bend, the Kusko is flowing clear.

Atchak said he would welcome the rumble of a big breakup.

"That's a beautiful sound to me," he said. "That's opening up our lifeline. To me, that's joy."

Managers are staying vigilant. "There's always a risk," Johnson said. "Everybody should be prepared."

Lisa Demer

Lisa Demer was a longtime reporter for the Anchorage Daily News and Alaska Dispatch News. Among her many assignments, she spent three years based in Bethel as the newspaper's western Alaska correspondent. She left the ADN in 2018.

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