Landslide Risks Along Park Roads Increase in a Warming Climate

Denali Park Road showing a displacement of 14 feet in a slide area in 2021. The road has since been closed while a solution is being engineered.

Climate change impacts many natural and cultural resources in parks, but infrastructure is also impacted, sometimes severely. In Alaska parks, infrastrucutre is fairly minimal, but roads can be difficult to maintain in harsh conditions and especially in areas underlain with thawing permafrost. Precipitation events (more rainfall and larger snow falls) are also increasing, contributing to road damage.

Mean annual air temperatures in Alaska parks have all made abrupt upward shifts in recent years, with many locations approaching or exceeding the freezing threshold. This magnitude of warming is occurring several decades earlier than expected. Using high-resolution climate model results, available from the Alaska Climate Adaptation Science Center, and NPS Inventory and Monitoring (I&M) weather station data, coupled with permafrost maps from the parks, the research team generated park-level assessments in three focus areas: the Denali Park Road, the McCarthy Road, and the proposed Ambler Road corridors. The analysis shows that large portions of Denali and Wrangell-St. Elias national parks and preserves are projected to have above-freezing mean annual air temperatures in the mid-century period (2021-2060), indicating an elevated risk for landslides. Southern portions of Gates of the Arctic National Park and Preserve are projected to have above-freezing mean annual air temperatures in the late-century period (2061-2100). Station observation trends of mean annual air temperature were largely consistent with the climate reanalysis data, and while observed summer precipitation trends were mixed, there was good climate model agreement of significantly wetter summers in the projected periods.

More Information

Assessing Risk to Alaska National Parks, Alaska Climate Adaptation Science Center
Scientists assess future landslide risk in Alaska's national parks, UAF News and Information, March 13, 2023

Learn more about geohazards.
See the most recent updates on the Pretty Rocks Landslide along Denali Park Road.

In the media:
Construction to start on bridge over landslide site in Denali National Park, Yereth Rosen, Alaska Beacon, January 16, 2023,

Climate Indicators of Landslide Risks on Alaska National Park Road Corridors

Abstract

Landslides along road corridors in Alaska national parks pose threats to public safety, visitor access, subsistence activities, and result in costly remediation of damaged infrastructure. Landslide risk in these areas, which contain near-surface permafrost, is associated with mean annual air temperatures (MAATs) above freezing and heavy precipitation events. Historical (1981–2020) values of MAAT and summer precipitation (JJA PCPT) from the fifth generation European Centre for Medium-Range Weather Forecasts (Reading, UK) atmospheric reanalysis (ERA5) were compared to mid-century (2021–2060) and late-century (2061–2100) downscaled climate model projections across Gates of the Arctic National Park and Preserve (GAAR), Denali National Park and Preserve (DENA), and Wrangell-St. Elias National Park and Preserve (WRST). ERA5 showed that all locations historically had MAAT values below freezing, but all three parks were warming significantly (0.3–0.6 °C per decade). Observed trends of MAAT from 18 stations showed warming trends with 11 of the 18 being significant at the 95% confidence level using the Mann–Kendall non-parametric test. Road corridor values are given for the: (1) proposed Ambler Road through GAAR, (2) Denali Park Road in DENA, and (3) McCarthy Road in WRST. Elevated risk from MAAT was projected in the mid-century period for the Denali Park Road and McCarthy Road and across all three park road corridors in the late-century period; elevated risk from JJA PCPT was projected in all periods for all road corridors.

Lader, R., P. Sousanes, U. S. Bhatt, J. E. Walsh, and P. A. Bieniek. 2023. Climate indicators of landslide risks on Alaska national park road corridors. Atmosphere 14(1): 34.