Warm weather to lead to mellow breakup, experts say

Warm weather and early snow melt, are conducive to a mellow break up. That was the message of forecasters during a teleconference Tuesday morning.  Alaska River Forecast Center Senior hydrologist Crane Johnson anticipates more of a mush out.

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Where the Charley River meets the Yukon. (Photo by USGS)
Where the Charley River meets the Yukon. (Photo by USGS)

“Generally, we’re turning towards a thermal breakup on the Yukon, Kuskokwim and other major interior rivers,” Johnson said. “We can expect that breakup will will earlier than an average at most locations and possibly the earliest on record at some locations.”

Warm spring weather allows ice to gradually rot, minimizing the chance of ice jam flooding, a scenario National Weather Service Climate Science and Service manager Rick Thoman says the records back up.

”Years where we had significant, moderate or major flooding on the Yukon River definitely has a cool tilt to the April and May temperatures,”said Thoman.

Thoman adds that current modeling indicates no sign of Alaska’s warmer than normal trend changing over the next month.

”The North American multi-model ensemble has been consistent for months, for the spring in Alaska showing this continuation of the very mild weather we’ve had since Christmas,” Thoman said.

Thoman and Johnson both emphasize that lack of snow cover over much of the state has exposed river ice to sun. The only Alaska River given a moderate to high chance of break up flooding is the Sag on the North Slope, where there’s heavy ice buildup, similar to last year, when flooding damaged the Dalton Highway near Deadhorse.

Dan Bross is a reporter at KUAC in Fairbanks.

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