Highway closure planned to remove large rock in canyon

A two-hour closure of U.S. 20/Wyoming 789 on Thursday, Dec. 7, in Wind River Canyon is intended to help a contractor successfully and safely bring a large rock off the canyon wall to the edge of the highway.

Wyoming Department of Transportation geologists have determined that the large rock needs to be removed from the rock wall prior to winter near the Fremont-Hot Springs county line.

"The two-hour highway closure is scheduled between 11 a.m. and 1 p.m., weather permitting," said WYDOT resident engineer Kaia Tharp of Thermopolis. "Leaving the rock in place would be a safety issue heading into next spring, according to WYDOT geologists, with the normal freeze/thaw cycle and expected normal rockfall due to melting snow and spring moisture."

The work zone where the rock will be removed is located above the highway at milepost 117.2 inside Wind River Canyon, roughly 16 miles south of Thermopolis, or about a mile north of the Wind River Canyon tunnels.

All work is dependent upon favorable weather.

Tharp said work is scheduled to begin Monday, Dec 4, with drilling and preparation of the site for blasting with explosives. "Drivers should expect 15-minute stop times Monday through Thursday morning," Tharp said. "Traffic will be slowed in the work zone with the use of flaggers. After blasting on Dec. 7, 15-minute stop delays are expected until all rocks are cleared from the roadway. The road may be closed again if all the rock does not come down during the first blast."

Citizens are being informed of the Dec. 7 closure in a number of ways, including through use of digital message signs near Shoshoni and Thermopolis.

Prime contractor Wilson Brothers Construction of Cowley is the prime contractor on the $600,000-plus effort to clean up rockfall from falling rock and mud slides this past spring inside Wind River Canyon between Shoshoni and Thermopolis. Contract completion is Dec. 15, 2017.

"We appreciate everyone's patience," Tharp said.