Denali Park operations altered due to Pretty Rocks Landslide

Some park operations at Denali National Park are currently altered due to the Pretty Rocks Landslide.

The Pretty Rocks landslide intersects the Denali Park Road near its midpoint at Mile 45.4 and displaces 100 yards of the full width of the road. In recent years this landslide has evolved from a minor maintenance concern to one that has caused substantial road restrictions.

The closure of the Denali Park Road at Mile 43 is expected to remain in place through summer 2026, while the Polychrome Area Plan is implemented.

The Pretty Rocks landslide has been active since at least the 1960s, and probably since well before the Denali Park Road was built through this area in 1930. According to the National Park Service website, before 2014, the landslide only caused small cracks in the road surface and required moderate maintenance every 2–3 years. However, in 2014, road maintenance crews noticed a substantial speed up, and by 2016, movement had further increased, causing a slump to develop in the road, and a monitoring program was begun. The rate of road movement within the landslide evolved from inches per year prior to 2014, to inches per month in 2017, inches per week in 2018, inches per day in 2019, and up to 0.65 inches per hour in 2021.

Pretty Rocks is one of several known landslides in the Polychrome Area, and one of the more than 140 mapped unstable slopes along the entire Park Road, according to the NPS website. The Polychrome Area Plan was developed with this in mind and addresses solutions not just for Pretty Rocks, but also for the nearby Bear Cave Landslide.

The NPS says that even though Pretty Rocks is currently the most problematic location, they are working with the Federal Highway Administration to manage the park road proactively and holistically in order to restore and maintain access along the entire length of the road.

To learn more about the bridge construction project that began at Pretty Rocks in 2023, and read about the Polychrome Area Plan, please visit www.nps.gov/dena/learn/nature/pretty-rocks.htm