Flooding caused by an ice jam on the Yukon River near Eagle appeared to have crested overnight Wednesday -- but meteorologists were monitoring the situation as well as the threat it could pose to another village downriver.
The National Weather Service extended a flood advisory for the Yukon near the Canadian border, originally set to expire at 10 a.m. Thursday, until 6 a.m. Friday. An initial advisory Wednesday evening reported minor flooding along the road linking Eagle and nearby Eagle Village, as well as yards of homes along the river's lower banks.
"The river is choked with ice and ice (floes) are spilling overbank as well," forecasters wrote. "Water levels will remain high and may fluctuate until the ice jam releases."
According to Ed Plumb with the Weather Service's Fairbanks office, a water level of 37.15 feet recorded Wednesday near Eagle represented the peak reported so far.
"We got ahold of a resident there this morning and the water crested last night early in the evening on Wednesday," Plumb said. "It has slowly come down overnight."
Forecasters also got word Wednesday night from a resident near the site of the jam at Calico Bluffs, about 10 miles downriver of Eagle.
"There was some ice movement, but the ice jam is still in place," Plumb said.
Plumb said forecasters' concerns about major flooding in Eagle, like the surge that devastated Eagle Village in 2009, have been alleviated by the absence this year of the snowpack at lower altitudes that helped feed that flood. The Yukon has also seen a more dispersed thermal breakup this year rather than a single breakup event flowing downriver, with villages along the lower Yukon already seeing ice clear last week.
"There isn't a large surge of water coming down the Yukon; the water levels upriver are pretty steady," Plumb said. "You end up with multiple areas where the river may be breaking up, versus when we have a solid push from snowmelt."
With the movement of ice at Calico Bluffs, Plumb said, the Weather Service is hoping to get aerial imagery Thursday morning of the river near Circle, about 160 miles downriver of Eagle. Ice from a failing jam at Eagle usually takes about five days to reach Circle, which generally faces a greater threat from rising waters.
"Circle is more prone to ice jam flooding than Eagle is," Plumb said. "They're lower on the riverbank."
Despite the absence of severe flooding so far, Plumb said, shifting ice can often cause new jams to form -- and new flooding concerns to emerge.
"That's always the fly in the ointment," Plumb said.
Correction: An initial version of this story inaccurately said Calico Bluff was 10 miles upriver, not downriver, of Eagle on the Yukon.