<p>Rock glaciers are perennially frozen bodies of ice and poorly sorted rock debris that flow downslope due to basal shear and deformation of interstitial ice. As common features in high mountain environments, rock glaciers constitute an important component of alpine hydrology and landscape evolution through release of seasonal meltwater and transport of debris downslope. Here, we use satellite-based interferometric synthetic aperture radar (InSAR) from 2015 to 2021 to identify and characterize rock glaciers in the La Sal Mountains of Utah, USA. Following the IPA Action Group guidelines, we created an inventory of 45 active and transitional rock glaciers in the La Sal Mountains based on mean InSAR velocity maps. La Sal Mountain rock glaciers have an average area of 0.09 km<sup>2</sup> and are found at a mean elevation of 3187 m, where mean annual air temperature and precipitation are estimated to be 2.44 °C and 1012 mm, respectively. The mean downslope velocity for the inventory is 3.58 ± 1.13 cm yr <sup>-1</sup> with individual rock glacier velocities ranging from 1.98 cm yr <sup>-1</sup> to 7.54 cm yr <sup>-1</sup>. Time-dependent deformation of 19 representative rock glaciers shows that rock glacier motion varies seasonally, with rates of up to 38.2 cm yr<sup>-1</sup> during the late summer. Average annual rock glacier velocities are also strongly correlated to the overall amount of precipitation received each year (R<sup>2</sup> = 0.97). Our results offer insight into environmental factors that may govern rock glacier kinematics, suggesting that rock glacier kinematics are controlled by the availability of liquid water.</p>

<p>Rock glaciers are common landforms in many alpine permaforst landscapes that play an important role in alpine hydrology and landscape evolution, principally through the release of seasonal meltwater and the downslope transport of coarse material. Here, we use satellite-based interferometric synthetic aperture radar (InSAR) to identify and monitor rock glaciers in the Western USA. We focus on the movement of active and transitional rock glaciers in Utah (Uinta, Wasatch, and La Sal Mountains), and Wyoming (Wind River Mountains) between 2015 and 2022. Using the new framework established by the International Permafrost Association (IPA) Action Group, we identified 255 active and transitional rock glaciers in the ~3500 km<sup>2</sup> Uinta Mountains, 45 rock glaciers in the ~200 km<sup>2</sup> La Sal Mountains, 55 rock glaciers in the ~135 km<sup>2</sup> Wasatch Mountains, and 120 rock glaciers in the ~3000 km<sup>2</sup> Wind River Mountains. These rock glaciers currently occur under different climatic regimes based on data from the 30 year (1991-2020) normal Parameter-elevation Relationships on Independent Slopes Model (PRISM). The La Sals and Wasatch are warmer and wetter with a mean annual air temperature (MAAT) of ~3.0± 1.9 ˚C and  2.7 ± 1.1 ˚C and a mean annual precipitation (MAP) of ~92 ± 13 cm and ~130 ± 17 cm, respectively, whereas the Uintas and Wind Rivers are cooler and drier with a MAAT of ~0.24 ± 1.4 ˚C and  -0.87 ± 1.4 ˚C and a MAP of ~87 ± 11 cm and ~81 ± 10 cm. The mean line-of-sight (LOS) velocities for individual rock glaciers range from ~1 to 10 cm/yr. We also examined the time-dependent relationship between the motion of the rock glaciers and local climatic drivers such as temperature and precipitation. We found that rock glaciers exhibit seasonal and annual velocity changes, likely driven by liquid water availability (from snowmelt and rainfall), with accelerated motion during summers and during wetter years. Our findings demonstrate the ability to use satellite InSAR to monitor rock glaciers over large areas and provide insight into the environmental factors that control their kinematics.</p>

No abstract