Ice Shifting, Signaling Record Early Break Up On Kuskokwim

Apr 19, 2016

Upriver of Napaimute, looking downstream. April 18, 2016. Photo courtesy of the National Weather Service, Alaska.

Middle Kuskokwim river ice is shifting and jamming as what’s predicted to be the Kuskokwim’s earliest break up on record gets underway.

“We had reports of ice shifting in Sleetmute [and] Chuathbaluk, a report of ice movement at Kalskag. And then ice was running fairly strong from Napaimute to Chuathbaluk, and then some ice shifting in Aniak as well,” Crane Johnson, National Weather Service hydrologist, said.

Johnson says the ice reports come from local observers, social media, and Bethel Search and Rescue collected Sunday and Monday.

With the ice already moving and temperatures above freezing, Johnson expects break up to occur this week. He’s predicting a thermal break up or a mush out. That’s when the ice melts in place rather than surging as a logged ice jam down the river, pushed by sudden snowmelt.

Johnson points to months of above average temperatures and low snowfall leading to the mush out. Bethel and areas further inland, he says, had their warmest January, February, and March on record this year, and that record is expected to generate another.

“It appears break up is occurring much earlier than normal, likely record early at most locations on the Kuskokwim,” Johnson said.

Johnson says with a mush out, large ice jams causing flooding are less likely to occur but remain a possibility.

Billy Alexie, a city council member in Upper Kalskag, says a small, seemingly harmless jam formed in front of the village Monday.

“But the water conditions haven’t raised very much, maybe about a foot or less and [then] dropped back down, so it’s not having any threat to the village,” Alexie said.

A little upriver in Aniak, resident Wade Morgan says water levels also remain low and the ice needle-like. He says the ice began shifting in front of Aniak around 6:30 p.m. Sunday.

“The ice is bank-to-bank right now, very slushy looking ice, some large sheets, but they’ll mush up,” Morgan said.

Monday afternoon a plane from the National Oceanic and Atmospheric Administration flew from the Holitna River to Napakiak taking aerial photographs of the Kuskokwim. You can read their report here.