Multi-decadal basal slip enhancement at Saskatchewan Glacier, Canadian Rocky Mountains

Abstract

Glacier motion responds dynamically to changing meltwater inputs, but the multi-decadal response of basal sliding to climate remains poorly constrained due to its sensitivity across multiple timescales. Observational records of glacier motion provide critical benchmarks to decode processes influencing glacier dynamics, but multi-decadal records that precede satellite observation and modern warming are rare. Here we present a record of motion in the ablation zone of Saskatchewan Glacier that spans seven decades. We combine in situ and remote-sensing observations to inform a first-order glacier flow model used to estimate the relative contributions of sliding and internal deformation on dynamics. We find a significant increase in basal sliding rates between melt-seasons in the 1950s and those in the 1990s and 2010s and explore three process-based explanations for this anomalous behavior: (i) the glacier surface steepened over seven decades, maintaining flow-driving stresses despite sustained thinning; (ii) the formation of a proglacial lake after 1955 may support elevated basal water pressures; and (iii) subglacial topography may cause dynamic responses specific to Saskatchewan Glacier. Although further constraints are necessary to ascertain which processes are of greatest importance for Saskatchewan Glacier's dynamic evolution, this record provides a benchmark for studies of multi-decadal glacier dynamics.

Climatic control on seasonal variations in mountain glacier surface velocity

“…Although field-based measurements can provide very U. Nanni et al: Climatic control on seasonal variations in mountain glacier surface velocity accurate data about glacier processes (e.g., Stevens et al, 2022;Nanni et al, 2022;Vincent et al, 2022), they require human presence and are generally limited to accessible areas, resulting in poor spatial and temporal coverage. In contrast, satellite imagery provides wide spatial coverage and is therefore an effective approach for retrieving glacier-flow characteristics in remote areas and on a large or even global scale (Li et al, 1998;Berthier et al, 2005;Scherler et al, 2008;Rignot et al, 2011;Dehecq et al, 2015Dehecq et al, , 2019Gardner et al, 2019;Millan et al, 2022).…”