Lasers will help map Zion’s historic highway tunnel

By HENRY BREAN LAS VEGAS REVIEW-JOURNAL

10 years ago

Zion-Mount Carmel Highway Tunnel (Courtesy)

Construction of the Zion-Mount Carmel Highway Tunnel at Zion National Park is shown in this undated photo from the late 1920s. (Courtesy National Park Service)

The Zion-Mount Carmel Highway Tunnel at Zion National Park is shown under construction in this undated photo from the late 1920s. (Courtesy National Park Service)

Construction of a concrete lining form in the Zion-Mount Carmel Highway Tunnel at Zion National Park is shown in this undated photo from the late 1920s. (Courtesy National Park Service)

A Civilian Conservation Corps crew works on a retaining wall along the new road leading to the Zion-Mount Carmel Highway Tunnel at Zion National Park in this undated photo. (Courtesy National Park Service)

A Civilian Conservation Corps crew works on a slope adjacent to the road leading to the Zion-Mount Carmel Highway Tunnel at Zion National Park in this undated photo. (Courtesy National Park Service)

The east portal of the Zion-Mount Carmel Highway Tunnel at Zion National Park is shown in this undated photo. (Courtesy National Park Service)

Workers repair a window gallery in the Zion-Mount Carmel Highway Tunnel at Zion National Park in this undated photo from the late 1920s. (Courtesy National Park Service)

Starting Thursday, Zion National Park in Southern Utah plans to light up its historic Zion-Mount Carmel Highway Tunnel with lasers, but don’t bother rushing up there with your electronic dance music or Pink Floyd cassettes.

The lasers will be used to create a detailed, three-dimensional model of the 85-year-old tunnel, which will be closed to traffic for the mapping.

Aly Baltrus, chief of interpretation for the park 150 miles northeast of Las Vegas, said the 3-D laser scanners should help Zion’s cultural resources staff learn more about the tunnel’s exact dimensions and the construction materials used to build it — information impossible to get without closing off the area for long periods.

As it is, the park is warning visitors to expect 20-30 minute delays at the tunnel on weekdays starting Thursday, and perhaps through March 27.

After March 16, the laser scanning work will be done between 6 and 8 a.m., when the tunnel will be be closed for up to 25 minutes at a time.

Construction of the 1.1 mile Zion-Mount Carmel Tunnel began in the late 1920s. The completed passage through a sandstone cliff hundreds of feet above the canyon floor was dedicated on July 4, 1930, as part of an effort to link national parks in the region.

“It was built as a main thoroughfare to help people get to Bryce Canyon and the Grand Canyon and complete that little tourism loop,” Baltrus said. “It is amazing what they were able to build.”

The 3-D scanning will also help park officials check the structure’s condition, especially after accidents or other incidents. Last year, for example, a tractor-trailer got stuck at the western end of the tunnel. And a few years ago, there was a car fire inside, Baltrus said.

The tunnel is off-limits to tractor-trailers and other large commercial vehicles, bicycles and pedestrians. Private vehicles wider than 7 feet 10 inches or taller than 11 feet 4 inches are allowed through with a special traffic-control permit.

More information is available on the park’s website, www.nps.gov/zion/planyourvisit/the-zion-mount-carmel-tunnel.htm.

Contact Henry Brean at hbrean@reviewjournal.com or 702-383-0350. Follow @RefriedBrean on Twitter.