An ongoing landslide in Denali National Park has prompted park officials to close the Denali Park Road for the rest of the season west of the 43-mile mark. Melting permafrost likely due to climate change has caused landslide movement rates that are “unprecedented in the history of the park road,” according to the National Park Service.
The 92-mile Denali Park Road is the only way to drive into the 4.7-million-acre national park. The continuing landslide at Pretty Rocks on Polychrome Pass near Mile 42 has caused rapid deterioration of the road in recent years, raising concern about how to maintain the road while safely accommodating visitors, Anchorage Daily News reports. According to a statement issued by the National Park Service:
โChanging climate is driving frozen ground to thaw, resulting in unpredictable and increasing landslide movement rates at Pretty Rocks that are unprecedented in the history of the park road. We cannot safely keep up with the accelerating rate of landslide movement caused by permafrost thaw currently occurring in association with the Pretty Rocks Landslide,โ Don Striker, Denaliโs Superintendent, said in the statement.
The Denali Park Road doesn’t normally close past the Teklanika Rest Area at Mile 30 until mid-September. Landslides at Pretty Rocks have been happening since at least the 1960s but they usually only cause small cracks in the road which require maintenance only every 2-3 years, according to the National Park Service’s statement. But in 2018, the downward movement of rocks, or ‘slumping,’ as geologists refer to it, increased to almost half an inch per day, and then to three and a half inches per day by August 2020. Then early August rains in 2021 likely increased that rate dramatically to now ten inches per day, according to the NPS.
“Climate change, with its associated warmer winter temperatures and increased precipitation, has taken what was previously a problem solved by maintenance staff performing road repairs and made a challenge too difficult to overcome with short-term solutions,” according to the NPS news release. “The Presidentโs Fiscal Year 2022 Budget Request for the National Park Service identifies specific funding for a construction solution at Polychrome Pass to ensure access is maintained. The project is currently in planning and design so construction would not likely begin until at least 2023.”
Westbound traffic beyond Mile 43 on the Park Road is currently only allowed for essential purposes, like facilitating seasonal closure of western park operations, the park service said. The full NPS news release can be read below.
News Release: Denali National Park Closes Section of Park Road Due to Landslide Activity
Denaliย Nationalย Parkย and Preserve announced thatย aย portion of the 92-mileย Denaliย Park Roadย will closeย todayย due to aย fast-movingย landslideย creating unsafe road conditionsย at Polychrome Pass.ย The Denali Park Road typically closesย to vehicle traffic beyond the Teklanika Rest Area (mile 30) in mid-September.
The vast majority ofย Denaliย National Park remainsย openย forย visitors.ย Buses will continue to allow access to Mile 42 of the Denali Park Road, the Denali Visitor Center continues to provide daily ranger services, and front-country trails and backcountry access remain open. Theย Kantishnaย airstrip also remains open.
Beginning today, August 24, westbound traffic beyond mile 43 of theย Denaliย Park Roadย will be restricted toย essentialย travel to facilitate the seasonalย closureย ofย western park operations, including private lodges and inholdings located in theย Kantishnaย area. All visitors currentlyย camping inย the Wonder Lake Campgroundย andย in backcountry areas west of Polychrome Pass will be relocated east of the closure over the next few days.ย Effective immediately, camper buses will not be available for backcountry trips pastย mile 42, near the East Fork Bridge.ย Park tour and transit buses willย alsoย continue to operate, but willย turn around atย mileย 42.
โChanging climate is driving frozen ground to thaw, resulting in unpredictable and increasing landslide movement rates at Pretty Rocks that are unprecedented in the history of the park road. Weย cannot safely keep up with the accelerating rate of landslide movement caused by permafrost thaw currently occurring in association with the Pretty Rocks Landslide,โย saidย Don Striker, Denaliโs Superintendent. โThe National Park Service is actively working with the Federal Highway Administration and other partners on a long-term solution to maintain road access at Pretty Rocks corner and across Polychrome Mountain.โ
Whatโs closedย in Denali National Park:
- The Denali Park Roadย west ofย mileย 43ย (East Fork Bridge)ย willย be closedย on August 24thย toย non-essentialย vehicles,ย as well as allย pedestrianย and bicycle traffic.
- Wonder Lake Campground (mile 89) will be closedย on Augustย 24thย for the remainder of the season.
- Eielson Visitor Center (mile 66) will be closedย on Augustย 24thย for the remainder of the season.
โWith our partners, we will shift to allow for a full experience along the portion of the road east of the landslide. Visitors will continue to have access to great wildlife viewing, views of Denali, front-country trails, and backcountry hiking and camping,โย ย saidย Brooke Merrell, deputy superintendent.
Landslides have impacted Pretty Rocks since at least the 1960sย butย until recently, only required maintenance every 2-3 years. During the 1990s, the landslide, which occurs below the roadbed,ย only caused small cracks in the road surface. However, by 2018 the slumping increased to almost half anย inch per day, and then to three and a half inches per day by Augustย 2020. Early August rains in 2021 appear to have triggered the rate to increase significantly, with much of the landslide currently moving downhill at over ten inches per day.
Climate change, with its associated warmer winter temperatures and increased precipitation, has taken what was previously a problem solved by maintenance staff performing road repairs and made a challenge too difficult to overcome with short-term solutions.ย The Presidentโsย Fiscal Yearย 2022 Budget Request for the National Park Serviceย identifiesย specific funding for a construction solution atย Polychromeย Pass to ensure access is maintained.ย The project isย currentlyย in planning and designย so construction would not likely beginย untilย at leastย 2023.