Assessing patterns of annual change to permafrost bluffs along the North Slope coast of Alaska using high-resolution imagery and elevation models

Rapid Fluvio-Thermal Erosion of a Yedoma Permafrost Cliff in the Lena River Delta

“…Lower rates were reported from the Yukon coast with mean erosion rates of 1.3 m yr −1 (Irrgang et al, 2018), Herschel Island with 0.7 m yr −1 (Obu et al, 2016), the Chukchi Sea coast on the northern Seward Peninsula of Alaska with 1.3 m yr −1 (Farquharson et al, 2018), or Barter Island (Alaskan Beaufort Sea) with 1.3 m yr −1 (Gibbs et al, 2019), keeping in mind that these values are long term averages of areas, where local and temporal maxima can be substantial higher (e.g., 8.1 m yr −1 for All numbers are including ice wedges as well as segregated and pore ice, which means that 88% of all the yedoma volumes given here consist of ice. Eroded volumes are given in millions (10 6 ) of m 3 .…”

“…central parts of a bluff on Barter Island (Gibbs et al, 2019), or 22 m yr −1 for active slumps from 2012 to 2013 on Herschel Island (Obu et al, 2017). However, when comparing Sobo-Sise Cliff to other locations at the coast, it is important to point out that different factors affect fluvial thermo-erosion compared to coastal erosion.…”

Attenuation of Ocean Surface Waves in Pancake and Frazil Sea Ice Along the Coast of the Chukchi Sea

“…Arctic coastlines are considered particularly vulnerable to these changing conditions, which pose a unique threat to biological systems, human communities, and infrastructure (Forbes, 2011). Indeed the erosion rates along the Arctic coast have been accelerating (Gibbs et al, 2015(Gibbs et al, , 2019Lantuit et al, 2012), and the length of the ice-free season appears to be directly related to the higher erosion rates (Barnhart et al, 2014). While warmer temperatures are an obvious driver of erosion, in particular in areas with permafrost bluffs, mechanical processes associated with wave activity are likewise considered a leading contribution (Overeem et al, 2011).…”

Seven Decades of Coastal Change at Barter Island, Alaska: Exploring the Importance of Waves and Temperature on Erosion of Coastal Permafrost Bluffs

“…Similar to permafrost bluffs elsewhere in the Arctic, primary bluff failure modes are a combination of thermal denudation on the bluff face throughout the summer and thermomechanical removal of debris material fronting the bluffs and niching of the base associated with waves and high-water levels (wind or storm surge) followed by rotational slumping and block collapse [1,2,[28][29][30][31]. Ground ice typically occupies 60-90% of the volume of near-surface deposits [16,32], and it is a major factor contributing to the high coastal erosion rates [33].…”

“…Retreat rates appear to be largely dependent on ice content, the frequency and intensity of storms, runup elevation, and seawater and air temperatures [34][35][36]. The pattern of change is predominantly landward retreat of the top of the bluffs, removal of the debris apron and subsequent niching at the base of the bluffs, followed by continued erosion of the bluff face and deposition of debris at the base of the bluff [29].…”