FAIRBANKS -- Damage assessments of hundreds of homes will move forward after Gov. Sarah Palin declared flooding across much of northern and Interior Alaska a disaster.

She made the declaration Monday in Fairbanks.

The declaration frees the state to use disaster-recovery programs to help repair homes, buildings and roads hit by the flooding.

Officials said flooding stretched across the Tanana River basin to hit cities and villages as far away as the North Slope Borough.

The Alaska Railroad said it was operating freight on its lines, and full passenger service was expected back Tuesday afternoon.

Gen. Craig Campbell directs the state's Department of Military and Veterans Affairs. He says it's too early to offer an estimate of the flood damage across the state, but suggested it's likely to be very expensive.

Meanwhile, Interior Alaska fisherman are worried that recent flooding will harm king salmon eggs deposited in rivers.

Female salmon dig holes called redds in gravel river bottoms to lay eggs before male fish fertilize them.

Virgil Umphenour, owner of Alaska Interior Fish Processors Inc. in Fairbanks, said eggs may be affected by flooding.

"If you have high water and super-fast current, the eggs will just go down the river as she's laying them," Umphenour said.

Also, gravel likely is washing down the river and could fill in holes faster than females can dig them, Umphenour said.

State fisheries biologists do not know what effect flooding will have on king salmon spawning in the Chena and Salcha rivers. The flood coincided with the peak of spawning.

"Most times when we've had floods, they happened later on, after the fish were done spawning," said Dan Bergstrom, Department of Fish and Game regional supervisor for the Yukon River. "This year is different because it's right on top of when they should be spawning."

As of July 29, an estimated 3,080 kings had been counted at the Moose Creek Dam on the Chena River. More than 2,600 kings had been counted in the Salcha River as of July 27.

The counts were high enough to meet the minimum escapement goals for each river.

While the effects of floods on spawning salmon are uncertain, high water stresses fish and forces them to use more energy fighting the current as they move up the river, said Pat Milligan, a biologist with the Canada Department of Fisheries and Oceans in Whitehorse, Yukon. If kings this year are smaller than normal, as many fishermen have reported, it may be more difficult for them to reach spawning grounds.

"It is a concern," Milligan said of the high water. "They have to have energy go get to the spawning grounds and then they have to have energy to spawn."