Closures of Wolf Creek Pass – like one that shut the pass for six hours last week – could plague U.S. Highway 160 travelers throughout the summer, a highway official said.

"Motorists who travel that corridor frequently should be aware that we’ll have this kind of challenge frequently while working with the rocky terrain," said Nancy Shanks, Colorado Department of Transportation spokeswoman.

CDOT is blasting on the east side of the pass to construct a 950-foot tunnel around the highway’s mile marker 175. On June 4, a blast brought tons of rock onto the road, forcing motorists to wait for six hours.

The rock slide was similar to one that closed the pass for 15 hours just two weeks ago.

"It can be kind of an enigma working with the geology up there," Shanks said.

The slide covered the pass at 2:30 p.m. One lane was opened shortly before the entire pass was closed for the night. One lane of the pass opened the next morning.

Normally, the pass will be closed from 7 p.m. to 7 a.m. Monday to Friday. Drivers can expect delays of up to 45 minutes between 7 a.m. and 7 p.m. Monday through Thursday, and on Fridays from 7 a.m. until late afternoon.

Shanks recommended that travelers go to the CDOT Web site for traffic alerts. The department usually posts warnings within 20 minutes of any slide.

"We’re working to make that a knee-jerk reaction," she said.

The CDOT road hot line is also available at 1-877-315-ROAD.