CHEHALIS, Wash. -- The Washington Department of Transportation reopened Interstate-5 at Chehalis Friday after the busy roadway was submerged in flood water.

Transportation officials began allowing commercial trucks over 10,000 pounds through at 10:50 a.m. Then, around 12:30, cars were allowed through.

Initially, the state had predicted I-5 would remain closed for up to four days. At one point, flood water was about 10 feet deep over the highway.

The "closed" signs first went up Wednesday night along a 20-mile stretch from Chehalis to just south of Olympia, requiring trucks to take a 440-mile detour on a north-south route from Seattle to Portland, Washington Transportation Secretary Paula Hammond said.

 Slideshow: Floodwater rushes over I-5

Photo courtesy: Gregg A. Pohll

A kayaker makes his way along the flooded interstate during flooding in December, 2007.

All three major east-west mountain pass highways through the Cascades were closed because of avalanche and mudslides dangers

Hammond called the situation "the worst of the worst" with I-5 and all major highway passes closed simultaneously for several days this week.

About 10,000 semi-trucks a day travel I-5 and the financial impact of the closure on freight movement is about $4 million a day. That's made worse by the Cascade pass closures: about 7,000 freights a day move over the passes.

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Crews said they would not be able to reopen Interstate 90 through Snoqualmie Pass on Thursday as they had hoped.

Stevens Pass and White Pass also remained closed by avalanches, slides and floodwater, cutting off east-west travel across Washington.

High water and slides have closed 62 highways statewide.

I-5 was closed for four days at Centralia during the flooding of December 2007.

The constant, heavy rain had stopped in western Washington Thursday but it could be days before floodwaters receded, all roads reopened and evacuees returned home.

The National Weather Service forecast major flooding on 18 rivers in Western Washington as several counties declared emergencies.

The Associated Press contributed to this report.