A landslide has blocked travel since 2021

Work has started on a $100 million steel truss bridge that will bypass the Pretty Rocks landslide in Denali National Park. The slide has closed roughly half of the park’s 92-mile road since August 2021. Granite Construction is leading the project.

For decades, National Park Service geologists have monitored the Pretty Rocks landslide at mile 43 of Denali’s sole access road. Its typical movement of a few inches per year caused regular but often minor road repair. 

But the slide accelerated in 2017, reaching nearly an inch per hour and eventually destroying the road. Scientists say dramatically warming air temperatures and increasingly heavy rainfall have deteriorated the ice and permafrost that once glued the slope together. Similar events are happening across Alaska and other high-latitude areas affected by rapid climate warming.

Park superintendent Brooke Merrell says the road closure impacts work at the park, including certain research and maintenance projects that lie beyond the slide. But she says it also provides new opportunities to observe wildlife responses to reduced traffic.

Tourism is also affected. Denali’s road is a premier destination for hundreds of thousands of annual visitors, many who are part of cruise ship package tours. Merrell says reactions varied last summer.

“For some, the landslide was inconsequential,” she says. “For others, it was a point of interest.”

The Park Service hopes to complete the bridge by 2025. Funding for the project comes from the 2021 Infrastructure Investment and Jobs Act and the 2022 omnibus budget bill.