Lower river breakup happened unexpectedly

by Angela Denning-Barnes on May 17, 2012

Loggers on the lower river, May 16. Photo courtesy of BSAR

Breakup is different every year, but this year was particularly unusual say some experts. While the middle Kuskokwim River was breaking up last week, snow machiners were traveling on the ice highway just a hundred miles downriver. Near Bethel, the ice looked white and flat. It measured 50 inches thick in some places.

Temperatures were freezing every night and didn’t get much warmer in the day.

So, with open water upriver and thick ice downriver, many experienced river- watchers predicted flooding. Three lower villages decided to evacuate over 100 elderly and chronic care patients as precautionary measures. The village of Kwethluk did experience flooding, but all other communities just saw high water.

Ben Balk, a National Weather Service Hydrologist who studied the breakup over the past week, said it was “about the best scenario we could have hoped for.”

“I have never seen anything like that,” said Balk, “where in the matter of 5 hours the ice down here from Bethel to Napaskiak just went from a white-ish color to brown.”

Balk, has followed breakup for several years, but he wasn’t the only one scratching his head. 30-year Search and Rescue leader, Peter Atchak said that he too hadn’t seen that kind of quick change before, from white to dark. He said it looked like the water was boiling from underneath the ice.

According to a post on the Bethel Search and Rescue’s website, quote: “Somehow, the thick ice became rubber-like and soft despite the cold winter and spring weather which made people believe Bethel might have a bad break-up.”

So, what really happened?

“We think that the open water upriver had time to be exposed to sunlight and warmer temperatures,” Balk said, “and that warmer water might have helped rot the ice from underneath.”

Balk says the river was a lot warmer than the cold, snowy weather people experienced above the ice. So, instead of seeing the ice deteriorate over a week, like a traditional breakup, it took only a few hours.

As of Thursday, high water was receding and all evacuees had returned to their homes.

The State Division of Homeland Security and Emergency Management has staff working in Kwethluk to help assess flood damages there.

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