The Washington Transportation Department reopened the North Cascades Highway at noon Thursday, after the second closure this summer due to mud and rock slides.

Spokesman Jeff Adamson in Wenatchee says the way was cleared Thursday morning when the last big boulder on the roadway was pulverized by a dynamite blast. The boulder was about 10-by-25-by-35 feet in size.

The section of Highway 20 was closed early last Friday morning by slides set off by heavy thunderstorms. Similar storms and slides closed the highway from Aug. 10 to Aug. 19, mostly in the area around Rainy Pass.

The North Cascades Highway also is closed each year by winter snow and opened April.