Oregon ? Heavy rain and flooding already blamed for three deaths in the Pacific Northwest washed out a major highway Thursday near Mount Hood and forced authorities to close 59 miles of road in Washington state.

The White River flowed over Oregon Highway 35 on Mount Hood’s eastern flank on Monday and Tuesday, cutting 20-foot-deep ruts through the pavement and sending boulders and trees rolling down the mountainside, said Bill Barnhart, an Oregon Department of Transportation manager.

Two creeks also wiped out a section of the same highway to the north, Barnhart said. Reopening the highway near Mount Hood is estimated to take $20 million.

Washington authorities decided to shut down a stretch of the North Cascades Highway on Thursday because of concerns about the stability of the ground under the roadbed.