FAIRBANKS (AP) -- Breakup arrived in force on the Brooks Range over the past week, gorging North Slope rivers and damaging buildings and roads.
Soaring temperatures melted a snowpack that had been kept largely intact by an unusually cold May.
That sent water cascading off the tundra, building three-foot waves in normally fordable streams and burying the Colville Village airstrip beneath 12 inches of water.
''This is the most dramatic breakup and the worst flood we've ever gone through,'' said Teena Helmericks, an air taxi operator who has lived in the Colville River delta for 40 years and is an official observer, with her husband, for the National Weather Service.
''Four days in a row of clear skies, and everything was melting all of a sudden,'' Helmericks told the Fairbanks Daily News-Miner. ''We have ice going by in the current that probably came from way up, up river. ... Ice that normally would have had plenty of time to melt before it was carried out into the delta.''
The lower Colville River forms the eastern border of the National Petroleum Reserve-Alaska. It was above flood stage Sunday.
The Sagavanirktok River, which parallels the Dalton Highway for much of its length, also was full of refrigerator- and table-top-sized ice Saturday.
''Everything just surged upward, with temperatures going from below normal to well above normal,'' said meteorologist Ted Fathauer.
That sent the snowpack, which was about normal for the season, racing downstream in one big melt-off, he said.
''Water content is much less important than temperature during melt season.''
Helmericks said her main building and most outbuildings had flooded. In Umiat, about 95 miles downriver, some buildings had as much as 18 inches of water inside, the Weather Service said.
''The valley was just about wall-to-wall flooding,'' said Helmericks of conditions near Umiat. ''That's just about unheard of.''
The National Weather Service expects the Colville River to drop back below flood stage at Umiat sometime Monday night.
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