16 Understanding the Past and Present Cryosphere of the Rocky Mountains

Alpine snow and ice play seminal roles in the environmental, geomorphic, and hydrologic processes. This session welcomes abstracts on scientific studies of the past and present cryosphere in the Rocky Mountains and beyond.

Monday, 18 May 2026
3:00 PM - 5:30 PM
Alvarado C

Ground Collapsing by 2050 due to Thawing Permafrost in Alaska

Paper number: 16-6
Program: Technical Sessions
Time: 5:00 PM – 5:20 PM

Authors

Abstract

A large portion of the Alaska terrain is underlain by regolith that contains excess ice (ice that in volume exceeds the natural pore space). Possible loss of the excess ice would lead to ground subsidence which in turn would disturb and destabilize the ground surface. Depending on the magnitude and local variations in excess ice content and soil properties the subsidence would lead to forest disturbances, increased soil erosion, hydrological changes, and potential increase in sediment supply to rivers and creeks.

Currently the best available long-term data of the ground subsidence come from a few field sites of limited spatial extent in Alaska and western Canada that are based on historical data (~20 years). Due to the projected warming of the air temperatures in Alaska in the coming decades there is a high expectation for widespread ground subsidence. To better understand the spatial variations in magnitudes of expected subsidence we set out to model and map the future ground subsidence across the North-Central Alaska, along the Dalton Highway corridor. We analyzed the current thermal regime on the dominant ecotypes on various amounts of excess soil ice. These in-situ observations and for the purpose-built thermal model coupled with the existing ecotype, excess ice maps and Global Climate Model projections allowed us to model the ground subsidence by 2050.

We run the model for three separate excess ice scenarios: 50%, 25%, and 0% near surface (0-5 m) excess ice. The results show the largest average subsidence by 2050 of (~0.5 m) in the southern part of the study area whereas only a few cm of subsidence was projected in the northern part of the study area. This broad variation is explained by the strong and persistent N-S climatic gradient. However, the small-scale spatial variation in the subsidence, shown in the map we created, is the result of spatial variations in both amounts of soil excess ice and the thermal regimes that are determined by various ecotypes.

Geological Society of America Abstracts with Programs. Vol. 58, No. 4

doi: 10.1130/abs/2026RM-410631

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