CHEHALIS, Wash. (AP) - The Lewis County sheriff's office has information that water is topping a dike near Chehalis.

Chehalis River floodwater is flowing deeper over the section of Interstate 5 that has been closed. The river is forecast to crest Thursday evening.

Meanwhile, Washington Department of Transportation officials said Thursday morning that it was likely that I-5 at Chehalis would remain closed throughout the weekend.

Calling it deja vu, Washington Transportation Secretary Paula Hammond said the flooding is similar to the December 2007 flood that caused a four-day blockage on the main north-south route in Western Washington.

Hammond said when the Chehalis River crests Thursday night, officials expect water to be 10 feet deep over the highway. After the water starts falling, crews plan to use pumps and breach a levy to help the water drain out.

Hammond said about 55,000 drivers travel I-5 in the area each day - 10,000 of them trucks - and the financial impact of the closure on freight movement is about $4 million a day.

Don Wagner, a WSDOT spokesman, said the only way for people to get from Portland to Seattle is to take a flight. There was no immediate detour established around the closure, and even Amtrak passenger service was shut down.

Those needing to get to eastern Washington can still head east through the Columbia River Gorge and head up Highway 97 toward Yakima, however, he said.

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In response to the closure, Horizon Air said Thursday it was offering a special flood fare of $119 each way between Seattle and Portland. The fare is being offered through Saturday.

The company said it was putting its spare aircraft to work for extra flights between the cities to meet the high demand. LEARN MORE

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